Before civil rights and aclu, situations like this were often resolved quietly, without outside help, and no questions. The BG just "went away". It's a shame that a person's right to defend his property has to include consideration of the probability of losing your shirt as a result. However, I would probably confront them with a 12 gage, and hope that the bore size and my attitude would be sufficient to stop the action. They can run if they wish, but their vehicle belongs to me. Years ago, we caught some poachers on our hunting lease. When they returned to their truck, they had five flats, and was two miles from the road. No questions were ever asked.