People are unbelievable, we live at the end of a dead end county road. It is pretty obvious where the road ends as it is hard surface and 40 feet wide. Our drive is gravel and about 12 feet wide with yard on both sides. People would drive down our drive and turn around in our turnaround in front of the out building. Probably averaged 2 a week, sometimes more. We put up a board entry with a 16' gate and a private drive sign. Problem solved, until we left the gate open so company that we knew was coming could get in. It was only open for about 1 hour and sure enough someone drove down and turned around, through the open gate, past the private drive no trespassing sign. At least no one has came though when the gate is shut. Just no respect for others property I guess.
For what it is worth, I researched gate openers quite a bit and several people were talking about having problems with the Mighty Mule. We ended up getting a U.S. Automatic and so far so good.