The Anonymous hacking collective yesterday succeeded in closing four San Francisco BART stations.
The group called for a physical protest after BART cut off cell service on Thursday in advance of planned demonstrations over the shooting of a homeless man by police officers last month.
Over the weekend, it also hacked into BART's computer systems to release customer data.
But yesterday's demonstrations attracted fewer than 100 people. Protesters, many wearing Guy Fawkes masks and clothing spattered with fake blood, gathered at around 5pm on the Civic Center Station platform, chanting "no justice, no peace, disband the BART police".
From here, they moved along Market Street to target more stations - and Powell, Embarcadero and Montgomery were all closed as a result.
Police in riot gear cleared the stations, but there were no arrests, and no injuries were reported.The stations were shut for about two hours.
And BART decided not to shut down cell service on this occasion - despite previous threats to do just that, and the swift introduction of a new rule saying that "No person shall conduct or participate in assemblies or demonstrations or engage in other expressive activities in the paid areas of BART stations, including BART cars and trains and BART station platforms."
The American Civil Liberties Union has called for an assurance from BART that it won't shut off service again - but without any success. It has, though, managed to persuade the FCC to investigate.