And I say again, people going into those situations need to use a service like Justin.TV which will broadcast the video to the world, and store it on Justin.TV servers.
Then the goons can do what they will but video taken before they throw the switch will still be available, not to mention it having been seen in real time (by those watching your "channel").
Could be as easy as, "I'll be broadcasting at 0800" to let folks know to watch... and they can be digitally recording as well.
Many of us have video cameras independent of cell phones. No “kill switch” effect there. If you’re deliberately joining such an incident, you’ll likely have time to grab it (or even buy one quick from darn near any electronics store, Walmart included) - if only for the much better optical zoom, as anything interesting may easily be too far for a cell phone camera to record well.