First off on the tree stand, I'd just ask him about it and if it is his tell him your putting one of yours on his property if he doesn't mind. If he hesitates explain to him you want it removed and not replaced or relocated on your property. If he does not claim it, remove it yourself and turn it into the local DNR office. But prior to that I'd ask him about the camera that is missing. See what kind of reaction you get and use your own judgement.

I was up there on the other side of county "O" last week and was so discouraged by all the ATVs off marked trials I packed up and went home.
I had scouted for a couple of days and had settled in on a stand off Walton road on county land. After an entire day in the stand I see a couple of deer feeding in my direction on the acorns. They were about 75 yards out when two ATVs roar in and cause them to change directions. I stayed and later two bucks with their nose to the ground followed the first set of does path off in the direct the ATVers pushed them.
I relocated my stand in the the next morning about a half mile away and sure enough different ATVs come through. Im not near any of the many designated ATV trails either time. Two of the guy were actually off any type of trail.

Other than my traditional gun hunt with a couple of buddies up there Im very discouraged about hunting the area. Not because of the deer sign or numbers but because of the idiots that frequent the area.

Go luck on getting your camera back.