If it was on public land then too bad for me. If private land then a different issue. For me I would try to assess the situation first. If the person had a firearm, then I may just not want to even make a point of it, as dying is not worth a tree stand to me. If no firearm I would likely approach and say something like "I think that you are mistaken or something, as that is my stand that you have. I would appreciate you putting it down and leaving it alone." I guess I would go from there.