The biggest problem I've ever had in the woods anywhere, relating to entities messing with my stuff, is mice. I've had holes chewed through a tent, holes chewed through a pack, the rubber grommet around my coffee mug chewed to shreds, food eaten that was left lying outside my rough strewn kitchen area, a birthday blueberry cheesecake cooling in storage nibbled at, and just the general unpleasantness of mice running over me at night, when I've slept out in the open.
I've had a tree limb fall on my car at a trailhead, but that was nature's fault, not damage by people. Or my own fault for not picking a spot at the base of a steep hill below a widow maker.
People are indirectly responsible for bears being a problem, but that generally is only in areas where there are camps where people feed the bears and bears are conditioned to associate people with food. This is not an issue on most hiking trails in PA, but could be more of an issue in areas like the Poconos, and is definitely an issue around campgrounds and shelters in the Catskills and Adirondacks, and probably near shelters on the Appalachian Trail.
I've had nothing but pleasant encounters with people while backpacking and using a base camp. I've been treated to wild mushrooms sauteed in butter, shared a snort or three of strong beverages, and talked for many hours on the experiences in life. Generally, I can't say that I've ever felt crowded, meaning that 99% of the folks you encounter don't feel the need to plop down their tent right next to the place you are camping.
I often don't carry a wallet, I take a single car key which is clipped to a hanger in my pack or fishing chest pack, and I keep my phone on me for GPS and camera purposes. I guess the camping gear has some value, but the way I look at it, if someone really needs the gear that bad, they need it more than me, and must be really hard up to have to steal it.
That being said, if I ever find a Slinger Fly Rod at a tent camp somewhere, I might just mess with your camp since it might be you ;-)
