We had a big problem with this, and the landowner of the farm I hunt thought it would be a good idea to make a sign that warned trespassers there were motion sensored cameras around. Either way it seems to have worked, because the signs he made look pretty professional, he even put a logo on them like a company made them or something. Haven't seen anyone yet! I know it sounds crazy, but I guess some people get kinda spooked when they think they might be on camera.