I had a stand stolen a few years back. It really upset me as I take ALL precautions and hunt on private land.

I take my treesteps out as high as I can reach (and I am 6'1) and lock my stand to the tree.

I went to check on things and I looked up and there was no stand...the tree wasn't even there. Then, I noticed the 5-6 foot lengths of tree scattered around with some treesteps sticking out of them.

I figured out who it was and got my stand back.

Just goes to show you that it doesn't matter how good your lock and chain are, unless you are attaching it to a metal pole!!

If I were you, I'd get 2 trail cameras. Mount one in view of your next stand and mount one along the trail that you figure the guy is using for access.