I have had only one experience of this sort that spooked me. About 12 years ago I was motorcycle touring, and I stopped at a supermarket to grab something to make for dinner later when I camped for the night. This was in the Finger Lakes area of NY. Anyway, as I came out of the store, there were a couple of rough looking guys in an old truck eyeballing me. I thought nothing of it at the time.
About an hour later, I was setting up my camp at this little "unofficial" spot I knew about off an obscure dirt road that a hiking trail crossed (sweat spot with a small waterfall). The very same truck with the same two guys slowly rolled past, stopped for a minute watching me, and then moved on.
It could have been nothing, but that was much too great of a coincidence for me so I packed up and moved on to another place, a Nat'l Forest campground with some other people around.
About an hour later, I was setting up my camp at this little "unofficial" spot I knew about off an obscure dirt road that a hiking trail crossed (sweat spot with a small waterfall). The very same truck with the same two guys slowly rolled past, stopped for a minute watching me, and then moved on.
It could have been nothing, but that was much too great of a coincidence for me so I packed up and moved on to another place, a Nat'l Forest campground with some other people around.