I recently had a situation where I was invited to hunt an area where there were numerous stands set up over about 600 acres.
The landowner gave me a tour in his SxS to show me the area, traffic zones, and where the stands were located.
Being that I'm a guest, I took extra care to ensure I wasn't close to anyone elses setup, even it it meant I didn't have the worlds greatest location.
Seems rude to me to have someone else sitting on my position that I put the hard work into to find, scout, learn, and plan for hunting it, especially if I hadn't invited them.
I'd do one of two things - I'd either give them a rash of grief in a highly vocal fashion and embarrass the snot out of them, or I'd pull their stand, deliver it to them, and politely inform them that they were right on top of mine and I don't appreciate their being inconsiderate.
If all else fails, inform them that you're hunting in the middle of a swamp/thicket/impossible terrain that you saw a MONSTER FREAK buck moving from, and shhhhhh....it's a secret.
Folks that will set up on your site would jump at such a thing, and set themselves up for it.