[Its me DUB]

Get a beater. Hit them with it (Yes, all of them. Use reverse if you have to). Ditch the beater.

 

[Its me DUB]

Have you thought about putting up a camera? Nothing real obvious, of course. I've been playing with cameras tied to my mac with motion detection software that saves jpgs when the image changes. Works pretty well. x10.com has some fair quality rigs that are wireless and can trigger a vcr, a friend of mine used that setup to catch someone stealing some tools from his shed. It sounds like these guys aren't that careful, might help collect some evidence.

Great idea.