While I applaud your situational awareness, I don't feel like it was the best idea to say anything to him. Especially since you were armed. If you feel that someone is engaged in unlawful activity, then by all means call 911.Let the police handle the police work. Like you said at the end of your post, your weapon is to defend life, not a car. I would hate to hear about anyone having to draw a weapon over a stupid car.