Which is why so many citizen groups have sprung up to film police. There are two such groups in Austin, there's a nationwide Copwatch organization, etc. Every experienced activist knows the first thing you do when police arrive on the scene is pull out your camera and start recording. It reduces the odds of someone getting hurt dramatically. It also reduces the odds of cops lying in court (though it does not prevent it entirely).

These days, when I see a black or brown person being detained by police, I tend to start recording from a safe distance. There's just too many instances of police violence in my city for me to consider it a safe situation (in the last year alone Austin police officers have shot and killed multiple unarmed black men...one was shot in the back of the head after a bank robbery he had nothing to do with...he just happened to be in the wrong place at the wrong time).

I didn't always feel this way about police, but these days, I view them as dangerous and unpredictable; since I'm white and middle class, I have a lot less to fear from police, but I recognize the extreme power imbalance there, and I'm much more aware of the history of police violence than I was in the past.