"When the police act as though cameras were the equivalent of guns pointed at them, there is a sense in which they are correct. Cameras have become the most effective weapon that ordinary people have to protect against and to expose police abuse. And the police want it to stop."
I also can't help but notice that all three states are anti-gun, Illinois and Massachusetts viciously so. Illinois, which for the benefit of the police revised their wiretapping law to make it crystal clear also absolutely forbids all civilian concealed carry (Wisconsin is the only other state with a total ban). The other two states are technically "may issue", with Maryland effectively never issue and Massachusetts at the whim of the local police chief.
These states don't want you carrying a gun and they're making clear they don't want you carrying and using a camera.
I've never heard of a policeman acting as though a camera was the equivalent of a gun. If you disagree, try pointing an actual gun at an armed policeman and see what happens.
These anti-camera laws are stupid, but the analogy to guns is silly. A better analogy would be "are cameras the new penises", because pointing one of those at a policeman will get you cautioned and possibly arrested but not shot.
http://gizmodo.com/comment/23878432
Any criminal who wants revenge on a cop is not going to be deterred by a law that forbids recording his face. For that matter, he wouldn't have been deterred in any of the cited cases, where if the cop committing a crime had known he was being captured on a camera he'd have confiscated it.