The FCC is calling for public comment on the legality of the San Francisco transit agency's interruption of cellular service in August 2011. Bay Area Rapid Transit had shut off cell phone service in its tunnels, anticipating a cell-phone-coordinated protest of the fatal shooting of passengers by the transit system's police.

The FCC promised a probe in December, and late this week the Commission announced (PDF) that it would be taking public comment until April 30, and will issue a reply by May 30.

SF transit officials claimed they cut service to protect public safety by dispersing the protest, but critics of that justification said it violated free speech and put people who might need to make emergency calls at risk. The FCC claims that 70 percent of emergency calls now come from mobile phones.

But the FCC's public notice also states that law enforcement personnel have raised concerns that, "wireless service could be used to trigger the detonation of an explosive device or to organize the activities of a violent flash mob," suggesting local government authorities like BART should be allowed to retain some autonomy over service in its stations.

The FCC's decision will most likely set a clear precedent for other local government agencies. So far, two electronic public comments have been posted (the FCC lets you post comments online or send them in by mail), both in favor of more severe restrictions on who can turn off cell phone service and when. "The only time it should be legal to shut down a wireless network is when it is necessary to do so to repair a defect, or when it is necessary to prevent an attack that is compromising the ability of the network to function." said one commenter, "the government and government agencies are not wise enough to judge any other scenario in which one might think about shutting down a network."