As longtime Reason readers are aware, police officers often don't like to be filmed by the public.
Recently, an officer in Pennsylvania got so fed up with being recorded that he drove his car on the sidewalk and threatened to run over a civilian, for the offense of filming on public property.
Courts have broadly held that civilians may legally record the police, so long as they don't physically interfere with officers doing their job. Even so, some officers chafe at the extra scrutiny: In recent years, officers have played copyrighted music in an attempt to keep the videos from being shared online. While underhanded, this is at least a relative improvement over the alternative, when officers would simply grab the phones from people's hands and arrest or pepper-spray them.