The Village Voice has an interesting article about New York's anti-dancing laws: The Safety Dance. Apparently the guy who runs NYC's only nightlife-industry organization also owns several large clubs, and is fully in support of the anti-dancing laws, because it causes less competition for him! What a weasel. He goes on to argue:
[...] that he and other club owners have -- in some cases -- poured millions of dollars into spaces that are zoned for a cabaret, and to allow a free-for-all is unfair: "The immediate eradication of the cabaret laws would be the same as if the city overnight announced that there was no longer a ceiling on the number of taxi medallions. [...] Can you imagine the outrage from people who had invested their life savings in a medallion only to find it rendered worthless in one fell swoop?"
Apparently protection of existing business models is more important than Constitutional rights: it doesn't matter whether a law is just, so long as corporations are making money from it. Hey, that line of thought is working for the RIAA and MPAA, why not this jackass.
The sidebar article, A Crash Course in Cabarets, enumerates the history of the anti-dancing laws in New York:
1926 The cabaret law is created to crack down on multiracial Harlem jazz clubs. "Most of the jazz in 1926 was being played in clubs in Harlem where there were mixed groups. And a lot of people considered jazz to be a mongrelized, degenerate music," says Paul Chevigny, author of Gigs: Jazz and the Cabaret Laws in New York City. The law defines a cabaret as "any room, place or space in the city in which any musical entertainment, singing, dancing or other form of amusement is permitted in connection with ... selling to the public food or drink, except eating or drinking places, which provide incidental musical entertainment, without dancing, either by mechanical devices, or by not more than three persons." In other words, a venue can't have dancing without a license.
I assume that San Francisco's club laws have similar racist and puritanical beginnings, especially given this city's early history, but I've never seen a history of the revisions to the law. I wonder if there's a changelog to the SF Police Code online somewhere...