Treestand
You should leave a note on the stand for a day and see what happens and if it is not removed then take it down as the owner has stated. I have had this same problem. The company I work for has 200 acres that they have allowed me to hunt on from now on. When I started going up to the land to do some scoutting I found 6 treestands on the land.
No one had the ok to hunt this land. So what I did was leave notes on all of them giving everyone one week to remove their stand and if was not done in that week I would remove them and they could call me to claim them.
Well I had to remove a few and a few guys called me. They tried to tell me lies about they have the right to hunt the land from the original owners or it was written in the sale of the land that they could hunt there. It was somewhat of a issue but all have been removed and I am looking forward to gun season starting Saturday.
The only bad news is I have to work this weekend but will be in the woods on Monday.
Hope it all works out for you and good luck hunting.