I used to hunt a management area that bordered private land. One year I kept seeing a guy slip across the line onto the management area and hunt it illegally when the gun season was open on private land but not on the management area, which was bow hunting only.
He never noticed me up a tree in camo bow hunting and he always sat at the base of the same tree when he slipped across the line to gun hunt. I made it a ritual to water his sitting spot every time I got down after dark to leave, he always left before I did. He never got the message and kept sitting in the same spot.
I finally got fed up with his trespassing and shouted at him " you are across the line and hunting illegally" at which point he left and didn't return.