As a criminal defense lawyer, I actually love body cameras. No one can lie about what happened when the entire encounter is on tape, and it's a great thing to harp on when there are convenient gaps in the recording.
Buddy of mine had a case where the cops did a completely illegal search of his client's cell phone on camera. Once he started making noise about that, the client was very quickly offered a great plea offer, ultimately resulting in a dismissal of all the charges.