I would call the game warden or the sheriff and ask them what to do with the stand. If theres no name and number on the stand you can’t be reasonably expected to notify the owner of it to remove it. It would pizz me off for sure but I wouldn't cause myself any further headaches for a few bucks for the stand. I would rather cause the trespasser headaches from the gamewarden. Theres a good chance they are putting stands on other properties as well not just your. I would probably tape a sign on the tree telling them to notify the game warden concerning the stand.
