Unofficial, off-the-radar clubs are nothing new. Speakeasies flourished during prohibition. New York, when I lived there anyway, had a handful of places like Milk and Honey or SubMercer, and it's not long ago that the kibosh was finally put on DC's (better known, but still low-profile) House of Secrets. California, a smoking-ban pioneer, has given rise to its share of "smokeasies."
Still, places like these have typically been clubs, places where folks could smoke or drink things frowned on by local authorities, or at least feel the thrill of being somewhere "underground." But Radley Balko points to a New York Times piece on a spate of underground restaurants seeking to turn out good food without having to deal with the hassle of licensing requirements and zoning regulations. Looks like the black market is going mainstream. As the regs proliferate, how long before it's taken for granted that an evening out will involve lawbreaking as a matter of course?