I don't really use the trail cameras I have as I don't have any true "convenient" places to set them up, but if I had things start disappearing, you can bet your arse I'd have them set up over "bait" in a position that they couldn't easily be stolen or noticed.
Sorry to hear about this Brett, I'd be fighting mad as well. I've taken a handful of stand that were left on mine or families property by TRESPASSERS, but never trespassed to take stands.