We need some young ambitious guy to do like in S. America and hang out at the parking area and watch tow rigs and trailers for say, $2.00 per rig per day. You pay him your money, and he writes down your plate numbers and keeps an eye on things. He'll need to have a cell phone and coverage, but just being there would keep tweakers moving on.

I saw this in Peru over 10 years ago, and it's common outside all major restaurants and shopping areas. There aren't enough police, and if there is no parking area "watcher", bad things happen. It was cheap; it works there. Might work here.