I think it comes down to is it legal to do the shooting and the land owner uses one of his tags. If it is I would ablige the man. If it isn't then you either call it experience and eat doe meat or find another place to hunt. The ethics question just about always has something to do with the law and if it isn't legal its not going to be ethical most likely.

Now I know ethics is something inside each of us to decide upon and legality doesn't equal ethics by any stretch. Just do what is right because it's still your name at the end of hte day.