A friends neighbor once cought somebody snooping around the driveway in between the houses and came out locked and loaded. He had the guy sprawled out spread eagle like the police do right on the driveway. After a few choice words he let him go with the firm warning if he comes back around they will never find his body. As far as i know it worked cuz hes had no problems since then which is good cuz im not so sure he was bluffing.
Myself i scrap not steal. I also dont leave messes in front of peoples homes and always try to be respectfull and polite. It often pays off because i get neighbors now giving me their scrap. Honesty really is the best policy. Besides that way ya dont get shot or worse - think deliverance and pulp fiction.