You could buy a sign that says this area is under video surveillance and one that says tresspasser will be prosecuted. But is it feasable to believe that someone has invested in a video surveillence system for the woods. I would just geta friend, set up two stands near the entry point, get some paintball guns crank up the pressure, then i would hunt them until they get the point. If they ever confront us you could say sorry we were having a paintball gun on MY PROPERTY and since this in MY PROPERTY i figured you were in the game cause on one else has permission to be here.