I hate when other people just come right in where your setup and think they own the place. I have been hunting the same piece of land (public) for 12yrs and every year I usually have 1 or 2 people come right in and walk past me to hunt. I stand up and say where the hell are you going....the usually say someting like " just taking a stroll.....looks likea good spot" I then respond (usually pissed by now) It is a nice spot and as you can see it is taken so get strolling somewhere else and I don't want to see you here again.
Most times it gets the person gone..sometimes it takes a bit more convincing but they leave.