I know its not a great feeling knowing someone might be hunting some of the same deer as you and they might be doing it illegally, but reporting it to the brickcompany and moving your stand is about the only option you have here. Like John Deer said, get to your stand as early as you can hopefully to beat out the other person and maybe even find out who they are and if in fact they are trespassing. I've delt with this in the past as well and your best bet is just to make sure your legal!!!!