I was threatened and harassed by a NYS Trooper for having the temerity to argue a traffic ticket in court; I showed up with the statute of the law and DMV recommendations. It made him look bad, as he didn't prepare for the incident. For my trouble, he tracked me down in the parking lot and threatened me. I encountered the same individual a couple months later while I was walking to a friend's house, and he threatened to arrest me. There's nothing at any point in this incident that I did that was criminal or belligerent. I was threatened by an individual for no other reason than him being in a position of power, while I had none.
Everything else I'd like to say to you is infractable. Use your imagination.
Multiple experiences that include threats and intimidation might make you think that videotaping encounters with cops isn't such a bad idea.