Two of your points -

3. Can other video from the camera be used against you? Do you normally drive like a jerk?
4. Does having a visible camera invite smash-and-grab theft?

- - - -

I have a post-it note on my dash. It says "Drive Meekly." There are too many (other - besides me) jerks out there to be ticked off at their bad behavior. "Teaching him a lesson" never works.

I have a Garmin GPS/dashcam in front with a dash-mount pad instead of a suction cup window mount. It has a 'sticky' weighted pad that just sits on the top of the dash. When I park I move it from the dash to the center console to discourage people from seeing it. I also have a budget rear-mounted cam on the back window.