Brett claims its for self protection, based on a prior incident. Having had similar experiences with backwoods LEOs I tend to believe him. I record all interactions with LEOs and private security. Saved me a lot of hassle several times, and has put several cops on report with their superiors. MP3 players that record are plentiful and cheap.
My attitude is about that of Brett's I am just smoother and older, which tends to get me hassled a good deal less.
Some cell phones record, too. They'll do in a pinch.
It appears that what he was trying to protect himself from was speeding tickets, having had the experience of believing he wasn't speeding when he got one. He apparently lives in a municipality that's used to keeping it's city treasury going with a speed gun. Since he couldn't produce any evidence it became a case of his word against the cop's, and the system says he can't win that. The video camera is pointed at his dash. The apparent intent is to record what he's doing, not what the cop is doing. That doesn't sound like a "setup" to me.