Here in Massachusetts, a lot of officers would consider recording with your phone intervening, and they would punish you for it. It took several cases of the state supreme court ruling that this was NOT OK before police finally curbed their behavior and stopped (or reduced greatly) their hassling of people recording. I think the court even got snarky about it at one point, saying something like "Despite our previous clarifications on this issue, police continue to violate citizens rights" or something similar.
It's not unreasonable for cops to be concerned by it - a lot of people were 'up in the cops' face about it - not just casual recording.
When you work in very difficult situations, and there are people filming you it can get dicey.
There are a lot of 'antagonists' out there who will do everything they can to prod cops into doing something they shouldn't, basically harassing them.
So it goes both ways.
Clearly - we should be allowed to video cops - but we also should not be allowed to harass or interfere with them unless there is something crazy happening.
But again - 'interfering' with a cop doing his job is a very risky thing because you never have the proper context, you don't know what is really going on. Physically assaulting a cop is grounds for him to fight back pretty aggressively.
Again in normal situations, it's not a problem, but there are tons of videos of cops trying to arrest someone, and then 'a mob' of friends trying to stop the cop.
Of course, they may feel their friend is being 'unjustly arrested' - but that's not up to you or I type thing. It can get pretty sketchy out there.
Check youtube. Cop tries to arrest, guy flees, cops put him down on the ground, 10 people try to harrass cop, pulling at his arms, pushing him back - very scary. Someone's going to get hurt.
It's a new dimension of civility and we all have to figure out the new social norms.
