My understanding is cellular service provision is highly regulated. Although it's in an "unusual" location, once it's established I wouldn't think it would be different from any other conventional cell service. The FCC or other agencies may have rules about whether service can be arbitrarily disabled.

>Who provides and pays for the service at the BART stations? If BART does, then I guess they have every right to shut it off if they like. If not, then disrupting somebody else's service should be a no no.
>
>I wish the GO system (commuter train) here would shut down the service so I wouldn't have to listen to people making phone calls just to say, "I'll talk to you when I get home." Believe me when I rode the GO, I heard nonsense like that all the time. And don't get me started on people who are convinced that everyone in adjoining provinces want's to hear their pointless babbling.
>
>>>>>>>So cut off cell phone communications to quell a protest?? This IS the United States isn't it?
>>>>>>>
>>>>>>>http://www.sfgate.com/cgi-bin/blogs/techchron/detail?entry_id=95300
>>>>>>
>>>>>>Your title is provocative - BART did not "jam" cell signals.
>>>>>
>>>>>Well what do you call it? ".... BART temporarily interrupted service at select BART stations as one of many tactics to ensure the safety of everyone on the platform..." http://www.bart.gov/news/articles/2011/news20110812.aspx
>>>>
>>>>Service interruption is not active jamming. You know that.
>>>>
>>>>http://en.wikipedia.org/wiki/Wireless_signal_jammer
>>>
>>>Ah yes I see that they didn't JAM the signal - they simply removed the power to underground service towers...which I would *think* is still illegal - surely the FCC has such rules (I'm trying to find out).
>>>A government agency turning off mobile-internet and phone service to quash a possible demonstration — sounds familiar doesn't it? Just like the speech suppression used by Middle Eastern dictators to quell dissent. It's nothing more than unlawful suppression of First Amendment speech!
>>
>>I was pointing out that it wasn't jamming, which to my mind is much more serious - in effect, an indiscriminate physical-layer DoS attack.
>>
>>The possible legal implications are interesting, I agree. How about this scenario:
>>
>>- BART receives credible news of potentially dangerous protests
>>- BART considers shutting off cell service, but decides not to
>>- During protests, people are injured or killed
>>- BART gets sued for not shutting off cell service
>>
>>A couple of other things worth thinking about:
>>
>>- Metro transit systems are "soft targets" that are choice targets for terrorist activities
>>- My understanding is cell phones are currently the triggers of choice for bombs or other devices