Yesterday on my way to work, a man in a pickup nearly clipped me with his mirror. I don't know if that was his intention. But he had plenty of room to swing around me. I caught up to him at the light, pulled out my wallet, knocked on his window, displayed my badge and "gently" advised him that it is now state law that he give at least 36" distance between his vehicle and any cyclist on the road. I advised him that he could be issued a summons for a misdemeanor and that if he had connected, it would have been vehicular assault - a felony. His reply - "I didn't see you." I countered with "Well, that would be reckless driving for observing the road - another misdemeanor."
I rarely pull my badge on anyone when off duty. But if I feel it will prevent anyone else from getting hurt, I will.