RE: Hunting ethics, you make the call!
Yeah there are people like that out there. No since fighting about it.
Just go about 20 feet from where he is sitting and leave a big steamer with the wind blowing right to him.
Or go a hundred yards up the trail just out of his sight and set up so the deer will have to go by you before they can get to him.
Depending on how mad you are, choose your option.