Bay Area commentators generally heralded this as a new day for the wonders of technology -- which, we were assured, would be socially empowering.
"I have to say, I love cell phone videos. Best thing that's ever happened to the BART police," said the Guardian's Tim Redmond.
Brittney Gilbert, of Eye On Blogs, was similarly enthused. "Sure, the BART station has security cameras, but videos by riders mean a wider range of views of the incident, which provides more information about what happened," she said. "Always a good thing."
Not necessarily: The best thing that's ever happened to the BART police may turn out to be the worst thing that's ever happened to social progress movements.
News has just emerged from Iran that the nation's first mixed-gender soccer game since 1979 was discovered by the authorities - and the "perpetrators" have been punished.
How could the authorities prove it happened? The same way the state intends to prove Johannes Mehserle shot Oscar Grant: Witnesses captured the crime on cellphone cameras and passed the videos along.
This should serve as a warning to Bay Area activists that -- however useful cell phone cameras were in this instance -- you may want to be a lot more cautious about this technology.
Some social protest depends upon public demonstration, but many of history's great acts of social protest and activism, such as the underground railroad, could probably never have happened if everyone was watching.
We can only imagine what cell phone cameras would have meant to the House Un-American Activities Committee in the 1950s, or the FBI as it searched under every stone for evidence to use against '60s radicals.
We don't have to imagine about the impact in Iran: We've just seen that it will be harder for men and women to treat each other like human beings in repressive countries if their neighbors have cell cams.
Certainly some good is coming out of this technology, but there's every likelihood that the state has a lot more to gain from our enhanced power to keep track of each other than we do from the enhanced power to keep track of the state.
Secrecy, in the end, may turn out to be good for human rights.