It is unlawful for any person to operate in the city any device, appliance, equipment or apparatus generating or causing high frequency oscillations or radiations which interfere with radio broadcast receiving apparatus or wireless receiving apparatus, except that a person duly licensed to practice medicine, osteopathy, chiropractic or dentistry by the state, in the course of the practice of his profession, may operate, or cause to be operated under his direct supervision, any machine necessary to give treatment, if all reasonable methods of preventing interference with radio broadcast receiving apparatus or wireless receiving apparatus has been applied.

This section shall not apply to radio stations, either broadcast, commercial or amateur, licensed by the federal government, or which are engaged in interstate communication, or to public utilities under the supervision of the state railroad commission. (Ord. No. 730, §§ 1, 2.)

20.2 Same—Notice to discontinue use or repair.

When an inspection and test has been made and it is found that any device, equipment, apparatus or appliance is being operated in violation of the preceding section, the owner or the operator of such device, equipment, apparatus or appliance shall be notified to discontinue the use of such device, equipment, apparatus or appliance, or to make additions, repairs or modifications thereof in order that the same may be operated in a manner which complies with the provisions of the preceding section. Such notice shall be personally served. In the event that the owner or operator of such device, equipment, appliance or apparatus does not, within forty-eight hours after service of notice to repair or discontinue the use of such device, equipment, apparatus or appliance, either entirely discontinue the use or repair the same or attach a silencing device thereto, so that it complies with the provisions of the preceding section, such owner, person in possession or operator shall be deemed to be operating such machine, device, appliance or apparatus in violation of the provisions of the preceding section. (Ord. No. 730, § 4.)

20.3 Repealed by Ordinance No. 1885.

20.4 Repealed by Ordinance No. 1983.

20.5 Bone, feathers, etc.—Burning prohibited.*

It is hereby declared to be a nuisance and it shall be unlawful for any person to burn or permit to be burned upon any premises in the city any bone, feathers, offal, flesh, hide or hair. (Ord. No. 875, § 10.)

* As to burning of garbage, etc., see § 16.4 of this Code.

20.6 Burials prohibited.

It shall be unlawful for any person to bury or inter, or cause to be buried or interred, the dead body of any human being within the city. (Ord. No. 392, § 9.)

20.7 City property—Reward for information concerning persons destroying.

The mayor is hereby authorized to offer a reward in a sum not to exceed twenty-five dollars to any person furnishing to the chief of police information causing the arrest and conviction of any person guilty of the destruction of or damage to any property of the city or any property for which the city is liable or charged with the maintenance. (Ord. No. 733, § 2.)

20.8 Prohibitions: Definitions: Waiters, waitresses, entertainers.

Every person is guilty of a misdemeanor who, while acting as a waiter, waitress or entertainer in an establishment which serves food, beverages or food and beverages, including, but not limited to, alcoholic beverages, for consumption on the premises of such establishment:

(a) Exposes his or her genitals, pubic hair, buttocks, natal cleft, perineum, anal region or pubic hair region; or

(b) Exposes any device, costume or covering which gives the appearance of or simulates the genitals, pubic hair, buttocks, natal cleft, perineum, anal region or pubic hair region; or

20.8A Counseling or assisting.

Every person is guilty of a misdemeanor who causes, permits, procures, counsels or assists any person to expose or simulate exposure as prohibited in Section 311.011. (Ord. No. 1635, § 1.)

20.8B Employment or payment not necessary for offense.

A person shall be deemed to be a waiter, waitress, or entertainer if such person acts in that capacity without regard to whether or not such person is paid any compensation by the management of the establishment in which the activity is performed. (Ord. No. 1635, § 1.)

20.8C Prohibitions: Definitions: Public performance.

Every person is guilty of a misdemeanor who, while participating in any live act, demonstration, or exhibition in any public place, place open to the public, or place open to public view:

(a) Exposes his or her genitals, pubic hair, buttocks, natal cleft, perineum, anal region or pubic hair region; or

(b) Exposes any device, costume or covering which gives the appearance of or simulates the genitals, pubic hair, buttocks, natal cleft, perineum, anal region or pubic hair region; or

20.8D Counseling or assisting.

Every person is guilty of a misdemeanor who causes, permits, procures, counsels or assists any person to expose or simulate exposure as prohibited in Section 311.021. (Ord. No. 1635, § 1.)

20.8E Exemption of theatrical establishments.

The provisions of Sections 20.8 through 20.8D shall not apply to a theater, concert hall or similar establishment which is primarily devoted to theatrical performances. (Ord. No. 1635, § 1.)

20.10 Repealed by Ordinance No. 1983.

20.11 Repealed by Ordinance No. 1983.

20.13 Draw poker.

It shall be unlawful for any person to participate in or allow others to participate in on his premises any game of draw poker. (Ord. No. 96, § 1; Ord. No. 1983 § 47.)

20.14 Guns, slingshots, etc.—Discharge prohibited.

It is hereby declared to be a nuisance and it shall be unlawful for any person to use or discharge in the city any pistol, rifle, shotgun, airgun, spring-gun, sling, slingshot or other device to throw or expel any bullet, slug, shot or any dangerous missile. (Ord. No. 875, § 25.)

20.15—20.19 Repealed by Ordinance No. 1983.

20.20 Knives—Carrying of certain types prohibited.

No person, except a peace officer, shall carry upon his person in plain view any snap-blade or spring-blade knife regardless of the length of the blade, or any knife with a blade three inches or more in length. (Ord. No. 1214, § 1; Ord. No. 1983, § 48.)

20.21 Minors—Loitering after 10:00 p.m.

It is unlawful for any minor under the age of eighteen years to loiter, idle, wander, or be in or upon the public streets, highways, roads, alleys, parks, playgrounds or other public grounds, public places, public buildings, places of amusement and eating places, vacant lots or any unsupervised place between the hours of ten p.m. and sunrise of the immediately following day. This section shall not apply when:

(a) The minor is accompanied by his or her parent, legal guardian or other adult person having the legal care or custody of the minor, or by his or her spouse eighteen years of age or older;

(b) The minor is on any errand directed by his or her parent or legal guardian or other adult person having the legal care or custody of the minor, or by his or her spouse eighteen years of age or older;

(c) The minor is returning directly home from a public meeting, or a place of public entertainment, such as a movie, play, sporting event, or school activity; or

(d) The presence of such minor in said place or places is connected with or required with respect to a business, trade, profession or occupation in which the minor is lawfully engaged. (Ord. No. 967, §§ 1, 2; Ord. No. 1983, § 48; Ord. No. 2027, § 2.)

20.21A Day-time loitering by minors.

It is unlawful for any minor under the age of eighteen years, who is subject to compulsory education or to compulsory continuation education to loiter, idle, wander, or be in or upon the public streets, highways, roads, alleys, parks, playgrounds or other public grounds, public places, public buildings, places of amusement and eating places, vacant lots or any unsupervised place during the hours of 8:30 a.m. and 1:30 p.m. on days when school is in session. This section does not apply:

A. When the minor is accompanied by his or her parent, guardian, or other adult person having the care or custody of the minor; or

B. When the minor is on an emergency errand directed by his or her parent or guardian or other adult person having care or custody of the minor; or

C. When the minor is going or coming directly from or to their place of gainful employment or to or from a medical appointment; or

D. To students who have permission to leave school campus for lunch or school related activity and have in their possession a valid, school-issued, off-campus permit; or

E. When the minor is excused from compulsory school attendance for any reason set forth in state law. (Ord. No. 2027, § 3; Ord. No. 2079, § 1.)

20.22—20.25 Repealed by Ordinance No. 1983.

20.25-1 Attracting customers by use of musical instruments, etc.

It is hereby declared to be a nuisance and it shall be unlawful for any person vending, advertising or soliciting the sale of or assisting in the vending, advertising or soliciting the sale of any kind of notions, food, merchandise or medicines in the city to use a musical device or to sing or call out or to make any noise to attract persons for the purpose of vending, advertising or soliciting the sale of such products; provided, however, that nothing herein shall be deemed to prohibit the use of any musical device emitting a sound or noise which does not last for more than two seconds and which is not repeated until after the lapse of one minute. (Ord. No. 1398, § 1.)

20.26 Pickets—Marching near other pickets.

No person, as a picket or as a member of a picket line, shall walk, march or be within twenty feet of another picket, except in passing, on the public sidewalks or streets, adjacent to any public place or any entrance, exit or approach to any place of business. (Ord. No. 1154, § 2.)

20.27 Pinball machines—Defined.

As used in the two following sections, the term “pinball machine” means any punchboard or any table game or device commonly known as a “pin game” or “marble game” or any claw, scoop or grab machine, or any horse racing machine or game, or any device similar thereto, the operation, use or play of which is controlled by placing therein any coin, plate, disk, plug, key or other device, or by the payment of any fee, or upon the payment or delivery of anything of value, or upon the making of any purchase. The term “pinball machine” shall not be construed to apply to any machine or game which is not predominantly a game of skill. (Ord. No. 1215, § 1; Ord. No. 1983, § 50.)

20.28 Same—Prohibited; exceptions.

It shall be unlawful for any person to keep, maintain, possess or have under his control, either as owner, lessee, agent, employee, mortgagee or otherwise, in any place except a building designed for and used exclusively for residence purposes or a part of a building, where such part was designed for and is used exclusively for residence purposes and any yards or courts used exclusively appurtenant thereto, any pinball machine. (Ord. No. 1215, § 2.)

20.29 Same—Destruction.

The chief of police shall destroy any pinball machine which is used, kept, placed or maintained in violation of the preceding section or of any statute or other ordinance, after the person owning, possessing or having control of such machine has pleaded guilty to or has been convicted of such violation and such violation has become final.

The chief of police shall deposit in the city treasury to the credit of the general fund all money contained in any pinball machine which he destroys pursuant to the provisions of this section. He shall destroy all other contents of any such machine.

The chief of police shall apply to the judge of any court which has custody of any machine subject to destruction under the terms of this section for an order releasing such machine to him for the purpose of complying with this section. (Ord. No. 1215, §§ 3 to 5.)

20.30 Police—False, unfounded, etc., reports to.

No person shall knowingly make any false, misleading or unfounded report, whether oral, written or otherwise, to any police officer of the city while such officer is acting in his official capacity. (Ord. No. 1145, § 1.)

20.31 Posting of certain property—Method.

Any person or governmental agency, department or instrumentality having possession or control of any of the facilities, plants or utility properties enumerated in the following section may post, at each entrance to any structure devoted to any use so enumerated, at each entrance to any fenced or enclosed area devoted to any such use, and at intervals of not more than three hundred feet around any area devoted to such use, substantial signs not less than one square foot in area, displaying prominently in addition to such other information as may be deemed desirable, the words, “TRESPASSING—LOITERING—FORBIDDEN BY LAW” in legible letters not less than two inches in height; provided, that any portion of any such structure or premises to which general public access is required in the normal use and operation thereof or where materials are delivered to or received by the public, shall not be so posted.

The “posted boundary” of any area shall be a line running from sign to sign, and such line need not conform to the legal boundary or legal description of any lot, parcel or acreage of land. (Ord. No. 820, § 2.)

20.32 Same—Where permitted.

The places which may be posted in accord with the preceding section are the following:

(a) Every reservoir, dam, pumping plant, aqueduct or pipe line of a public water system.

(b) Every generating plant, receiving station, distributing station and transmission line of a company or agency furnishing electrical energy.

(c) Every gas generating plant, compressor plant, gas holder, gas tank and gas main used for the production, storage and distribution of gas.

(d) Every plant or vital part thereof or other principal property essential to rendering telephone or telegraph service.

(e) Every radio broadcasting central plant or station.

(f) Every railroad bridge or tunnel. (Ord. No. 820, § 3.)

20.33 Same—Trespassing* or loitering on posted premises.

When any premises are posted as provided in the two preceding sections, it shall be unlawful for any person to go upon or to remain upon any place within the posted boundary of any such premises, or to enter or to remain in any such posted structure, without having upon his person the express written consent of the person, department or agency lawfully in possession or control thereof.

It shall likewise be unlawful for any person to loiter in the immediate vicinity of any premises so posted while having in his possession any explosive, tool or device of whatever character capable of doing harm or damage to any structure, machinery, equipment or other property of a similar or dissimilar character, installed or located upon such posted premises or area.

This section shall not apply to any entry in the course of duty of any peace officer nor to any person traversing an established and existing public sidewalk, street or highway. (Ord. No. 820, §§ 4 to 6.)

* For state law as to trespass generally, see P.C., § 602.

20.34 Same—Destruction of signs.

Every person who tears down, defaces, or destroys, or causes to be torn down, defaced or destroyed, any sign placed or posted under the provisions of sections 20.31 and 20.32 of this Code, without the consent of the person or governmental agency, department or instrumentality having possession or control of the premises on which such sign has been erected, shall be guilty of a misdemeanor. (Ord. No. 820, § 7.)

20.35 Public places and entrances, etc., to places of business—Blocking prohibited.

No person shall block, impede or obstruct any public place or any entrance, exit or approach to any place of business in or upon any public place in a manner calculated or with the intent to prevent, delay, hinder or interfere with the free passage there along or therethrough of any other person, either a pedestrian or an operator of a motor vehicle, who is entering, occupying or leaving any place of business, or who is performing any services or labor, or who is seeking or obtaining employment, or who is purchasing, selling, using, delivering, transporting or receiving any goods, wares, merchandise, services, entertainment, accommodations or articles or who is attempting or seeking to do any of the foregoing, or prevent, delay, hinder or interfere with the free passage therealong or therethrough of any vehicle or conveyance operated by or in the custody of any such other person or in which any such other person is riding or attempting to ride. (Ord. No. 1154, § 1.)

20.36 Repealed by Ordinance No. 1983.

20.37 Repealed by Ordinance No. 1983.

20.38 Trains—Blocking streets.

It shall be unlawful for the operator of any steam, diesel or electric railway train or car to operate the same in such a manner as to prevent the use of any street for purposes of travel for a period of time longer than five minutes. (Ord. No. 1106, § 11.03.)

20.39 Same—Speed.

The operator of a train upon a street shall operate the same at a careful and prudent speed subject to the limitations as prescribed in the Vehicle Code of the state for vehicles.* (Ord. No. 1106, § 11.04.)

* See Veh. C.A., §§ 510 to 517.

20.40 Repealed by Ordinance No. 1983.

20.41 Graffiti—Prohibition.

It shall be unlawful for any person to paint, chalk, or otherwise apply graffiti or other inscribed material on public or privately owned permanent structures located on public or privately owned real property within the city. (Ord. No. 1729, § 1.)

20.41A Same—Removal by violator.

Any person applying graffiti within the city shall have the duty to remove the same within twenty-four hours after notice by the city or by the public or private owner of the property involved. Failure of any person to so remove graffiti shall constitute an additional violation. Where graffiti is applied by juveniles, the parent or parents shall be responsible for such removal or for the payment therefor. (Ord. No. 1729, § 1.)

20.41B Same—Removal by owner.

It is hereby declared to be a public nuisance for the owner of any property, public or private, to permit graffiti to remain thereon for more than seventy-two hours after notice from the city to remove the same. Abatement proceedings shall be conducted pursuant to Chapter 24 of this code. (Ord. No. 1729, § 1; Ord. No. 1983, § 52; amended during 4/04 supplement.)

20.41C Same—Public removal.

After a finding by the city council that any graffiti or other inscribed material is obnoxious—and after securing, in the case of a publicly owned structure, the consent of the public entity having jurisdiction thereof, and in the case of the privately owned structure, after securing the consent of the owner thereof—the city council may order, at public expense, the removal of such graffiti or other inscribed material. (Ord. No. 1729, § 1.)

20.41D Same—Misdemeanor.

Violation of sections 20.41 through 20.41C is declared unlawful and shall constitute a misdemeanor, punishable by a fine of not to exceed one thousand dollars, or imprisonment for not to exceed six months, or both. Every day of such violation shall constitute a separate offense. (Ord. 1729, § 1.)

20.42 Bicycles and wheeled toys—Definitions.

For the purpose of these sections 20.42 through 20.42D certain words and terms are hereinafter defined and shall have the meaning thus ascribed:

(a) “Bicycle” includes every device propelled in whole or in part by human power upon which a person may ride, having two or more tandem wheels any one of which is over fourteen inches in diameter.

(b) “Business district” shall be that defined by the Vehicle Code of the state.

(c) “Place of public assembly” includes all buildings or areas where persons congregate from time to time, exclusive of those within business districts as herein defined.

(d) “Sidewalk” means that area adjacent to a travelled roadway, whether hard surfaced or not, upon which the public is customarily invited or permitted to walk or otherwise use.

(e) “Wheeled toy” includes all other wheeled objects regardless of motive power, not classified as bicycles in this Code nor as vehicles in the Vehicle Code of the state, and specifically includes, but without limitation, rollerskates, skateboards, coasters, scooters and toy vehicles. (Ord. No. 1761, § 1.)

20.42A Same—Business sidewalk operation prohibited.

No person shall use or operate any bicycle or wheeled toy upon any sidewalk in a business district or adjacent to any place of public assembly. (Ord. No. 1761, § 1.)

20.42B Wheeled toys prohibited on streets.

No person shall use, operate, park or leave any wheeled toy upon the travelled way of any public street or alley. (Ord. No. 1761, § 1.)

20.42C Bicycles and wheeled toys—Parking restrictions.

No person shall park or leave any bicycle or wheeled toy upon any street or alley, nor upon any sidewalk in any business district or adjacent to any place of public assembly in such manner as to obstruct or hinder the free passage of pedestrians or other vehicles or devices permitted to use the same. Any bicycle or wheeled toy found in violation of this section may be impounded by the police department and returned to the owner under such reasonable conditions as may be established by the chief of police. (Ord. No. 1761, § 1.)

20.42D Same—Exception from regulations.

Devices designed, intended and used solely for the transportation of infants, invalids or incapacitated persons, or devices designed, intended and used for the transportation of merchandise to or from the place of purchase, and other wheeled devices when being used for either of such purposes, shall be exempted from the regulations imposed by these sections 20.42 through 20.42D. Likewise, the regulations specified in sections 20.42 through 20.42D shall not apply to a place of public assembly when it is not open or in use, nor shall they apply if the person in charge of such place of public assembly expressly waives the same. (Ord. No. 1761, § 1.)

20.43 Repealed by Ordinance No. 1983.

20.50 Burglar alarms systems.

(a) DEFINITIONS. As used herein the words hereinafter defined are used as so defined unless it is apparent from the context that a different meaning is intended.

(b) ALARM SYSTEM. “Alarm system” means any device, whether known as a burglary, robbery or intrusion alarm, or by any other name, which is used for the detection of an unauthorized entry into a building, structure or facility. It shall include not only those devices which emit a signal within the protected premises only, are supervised by the proprietor of the premises where located, and are otherwise known as “proprietary alarm systems,” but shall also include any remote or silent signal devices. Auxiliary devices installed by a telephone company to protect telephone company systems which might be damaged or disrupted by the use of an alarm system are not included in this definition.

(c) ALARM OWNER. “Alarm owner” means the person who owns, leases, rents, uses or makes available for use by his agents, employees, representatives or family, any alarm system.

(d) FALSE ALARM. “False alarm” means an alarm signal activated by any cause other than the commission or attempted commission of an unauthorized entry which the alarm system is designed to detect. An alarm signal activated by violent conditions of nature or other extraordinary circumstances not subject to the control of the alarm owner shall not constitute a false alarm.

(e) AUDIBLE ALARM. “Audible alarm” means a device designed to notify persons in the immediate vicinity of the protected premises by emission of an audible sound of an unauthorized entry on the premises.

(f) DIRECT DIAL DEVICE. “Direct dial device” means a device which is connected to a telephone line and upon activation of an alarm system, automatically dials a predetermined telephone number and transmits a message or signal indicating a need for emergency response.

(g) ALARM REQUIREMENT. For every alarm, the alarm owner or user thereof, shall post the names and telephone numbers of persons to be notified to render repairs and service during any hour of the day or night during which the alarm is operated. An audible alarm shall terminate its operation, or the audible alarm shall automatically reset, within fifteen minutes of its being activated.

(1) Direct dial alarms will be programmed to telephone numbers only as designated by the chief of police.

(h) FALSE ALARM. No person shall knowingly turn in a false alarm. This section does not prohibit a test of an alarm system as permitted in advance by the police department.

(i) PUBLIC NUISANCE ALARMS. Any alarm system which generates more than three false alarms in any twelve-month period shall constitute a public nuisance due to the inordinate response time and risk attributable thereto. No person shall own, use or operate an alarm system classified as a public nuisance hereunder.

(j) EXEMPTIONS. The provision of subsection (i) of this section is not applicable to audible alarms affixed to motor vehicles or to a public telephone utility whose only duty is to furnish telephone service pursuant to tariffs on file with the California Public Utilities Commission.

(k) CORRECTIVE ACTION. Upon the first violation of subsection (i) of this section the chief of police shall serve a written notice on the violator describing the violation and specifying that the causes of the violation shall be corrected within ten days of the date of service of the written notice. No further action shall be taken; provided, that the chief of police determines that the causes of the violation have been removed or fully corrected within the time period specified in this section.

(l) PENALTY. Any alarm owner or user about to be cited for violation of subsection (i) of this section may avoid such process by paying a civil penalty to the director of finance of twenty-five dollars for the first offense, seventy-five dollars for the second, and one hundred fifty dollars for the third and subsequent offenses.

(m) SEVERABILITY. If any provisions or clause of this section or application thereof to any persons or circumstances is held invalid, such invalidity shall not affect other provisions or applications of this section which can be given effect without the invalid provision or application, and to this end the provisions of this section are declared to be severable. (Ord. No. 1816, § 1.)

20.51 Juvenile detention cost recovery.

(a) Responsibility for Costs. When, based on a finding of civil liability or criminal conviction in any one or more of the instances as described in this subsection, a juvenile (under eighteen years of age) in accordance with the provisions of Welfare and Institutions Code Section 602, is detained for a period in excess of one hour, and the detention required the supervision of the juvenile offender by a police department employee(s), then the parent(s) or legal guardian(s) having custody and control of the juvenile shall be jointly and severally liable for the cost of providing such police personnel over and above the services normally provided by the department. The fee assessed against such parent(s) or guardian(s) shall be set by resolution. The city reserves its legal options to elect any other legal remedies when the costs exceed limits set by resolution.

(1) Wilful Misconduct. Any act of wilful misconduct of a minor which results in injury or death to another person or in any injury to the property of another.

(2) Knowledge of Prior Misconduct. Any misconduct of a minor based on repeated and specific violative behavior, such that the parent or guardian reasonably has knowledge of and the opportunity to correct the specific propensity on the part of the minor.

(3) Theft from Merchant or Library. Any act of wilful misconduct of a minor which constitutes petty theft regarding merchandise from a merchant or library materials or books from a library facility.

(4) Permitted Access to Firearms. Any misconduct of a minor based on repeated access to firearms or other deadly instruments, such that the parent or guardian reasonably has knowledge of and the opportunity to remove access of the minor to the deadly instrument.

(5) Contribution to the Delinquency of a Minor. Any misconduct of a minor based on the parent or guardian contributing to the delinquency of the minor, including one who by act or omission encourages a minor to fail or refuse to conform to lawful order of the juvenile court.

(b) Accounting and Billing.

(1) Whenever a juvenile (under eighteen years of age) is detained by the police department pursuant to subsection (a) of this section for the commission of a public offense, and that detention exceeds one hour, a copy of the crime and/or detention report shall be forwarded to the chief of police, or other division head, as may be the case, for review. The chief of police, or other division head, will ensure that appropriate billing occurs.

(2) Any and all personnel who may be assigned by the city to detain, process or supervise the detention of a juvenile offender shall be deemed to be on special assignment as employees of the city, except that the rate of pay for such special assignment shall be set forth herein. The pay for each employee thus assigned shall be at the hourly rate of 1.5 times the base hourly salary of the employee. The chief of police, or other division head, shall report to the director of finance the name of the parent(s) and/or guardian(s) of the individual requiring these services, and the names of the employees so assigned and the number of hours of such assignment. The director of finance shall thereupon bill the person for the amount paid to each plus the cost of workmen’s compensation charges and other administrative costs. Any failure of the person to make payment shall constitute debt due solely to the city.

(c) Administrative Rules and Regulations. The chief of police may adopt administrative rules and regulations for the purpose of implementing the provisions of this section. (Ord. No. 2010, § 1.)

20.52 Repairing of vehicles.

No person shall repair, or cause to be repaired, grease, or cause to be greased, dismantle, or cause to be dismantled, or assemble, or cause to be assembled, any vehicle (as defined in the California Vehicle Code), or any part thereof, upon a public right-of-way within the city; provided, that temporary emergency repairs may be made upon a public right-of-way. (Ord. No. 2094-B, § 1.)

CHAPTER 20OFFENSES—MISCELLANEOUS

20.1 Appliances, equipment, etc., which interfere with radio receivers—Use prohibited; exceptions.