Firstly, I'd say it's debate able whether a corporation can disconnect public use communication services they've installed without notifying the public prior to

Firstly, I'd say it's debate able whether a corporation can disconnect public use communication services they've installed without notifying the public prior to disconnection. However, that debate is moot. BART is a government organization. Disconnection of communication services by a government organization for the express intent of preventing public demonstrations is a rather blatant violation of the 1st Amendment.