You declined to accept the offer of hunting the land so you don't have permission. If you shoot the deer you are a poacher just like the person who did it on your land. The fact that it was a great deer isn't relevant...only a temptation. I do admire the way you dealt with the original guy especially since he had a youth hunter with him. Unfortunately the kid will probably grow up to be the same type of hunter/ poacher that his father is.