I have had this happen twice.
First time - Ladder stand 6 feet off our property line facing into our property. Walked back to camp, put up a ladder stand 6 feet from the property line on our side. Got into the stand an hour before light. 30 minutes before light, had a guy come and get into his ladder stand. Once it was light enough to make anything out. I waved, he screamed and got down and left. Next day the ladder was gone. I win.
Second time - Ground box blind 10 yards off out property line. The guys threw apples 35 yards away from their blind on our property. We moved the apples 30 more yards onto our property, hung a 10x20 brown tarp in front of their window and hunted on our side of the tarp. Used a climber to hunt out of on my side of the tarp. Guy came in got in blind, finally saw tarp, started walking to it, I said from above, "I wouldn't touch that, I already have you on camera and you are trespassing where you stand." He turned around and left. The box blind was gone the next day. Killed a doe the next day eating the apples.