A number of years ago, I had a similar thing happen. I had posted on a hillside overlooking an oak flat, and a few minutes before legal shooting time, a guy walked in and posted less than 50 yards below me. I stewed about it for a short time, then shouted out to him, " Looks like a good spot, doesn' t it." He turned around and said, " Oh golly. I didn' t see you there, buddy." He didn' t move, so I kept up the conversation for awhile. Eventually, he got the idea. If I wasn' t going to be able to hunt here, neither was he. He left. About an hour later, I took a nice buck. I never saw the jerk again.