In a 6-to-5 vote, San Francisco’s Board of Supervisors voted Tuesday to ban public nudity – specifically, exposing one’s genitals on streets and on public transit. In other words, no bare buns on the BART.

Nudists could be fined $100 for a first-time offense; rebel nudists found naked a third time within a year will be fined $500 and could face up to a year in jail.

Exceptions to the ban: Children under five years and nudists in parades, fairs or festivals held under a city permit.

The ordinance was introduced by Supervisor Scott Wiener, who said he had heard increasing complaints from residents in San Francisco’s traditionally gay Castro District about a roaming band of increasingly bold naked men, the AP reported.