As to the "move or live with it" respondents, there is a 3rd choice: make it uncomfortable for them to be there.
Ahhh, perfect example of the "entitled" attitude. Sorry dude, you don't own the campground. If someone did that to you, you'd be the first to complain to management to have them thrown out. It's not your "right" to hog an area of the campground just because someone doesn't play by your rules. If someone camps near you your RESPECTFUL choice is to suck it up or move. Period. It's communal living that requires the establishment and respect of boundaries-from all.