Hate to hear that about that part of Ohio. Things sure have changed over there with all the development. The dnr might be able to help, doubtfull but if these guys are doing this it's a good bet they will be hunting illegaly. Might just tick them off more.

Sounds like you need to catch them and put a stop to it. Sounds like the spot is as good as lost anyways. Catch them and prosecute. If they do something that could result in your harm that's a serious offense. Got a catch them. I used to tie thread across trails to see what kind of deer came through, low on the trail and high, only bucks would break the high ones. Might be able to adapt something like that to follow them in and out. If they come from another stand, find that owner.

Go with out a cushion for starters.

How is it these guys know what you shot? That's another problem right there. Perfect way to lose a spot. Story as old as Hezikiah who showed others his trophys. They returned and took them.