A couple years ago I was in the bathroom at my local mall. I'm in the stall, doing my business, and I notice a shadow going back and forth in the door crack. I don't really pay attention to it, and when I walk out there's a guy by the door rubbing his pants. I assumed he spilled something and was cleaning it off.
When I walk out of the bathroom, there's another guy standing there. He approaches me and tells me that some guy was watching me through the door crack and rubbing his pants weirdly. He describes what he looks like, and sure enough it's the same guy I saw when I first walked out of the stall.
I head straight to security, and after 15 minutes of finding the guy using the camera system in the mall (which was surprisingly high-tech for a small Canadian town mall), they tell me that they were looking for this guy for months. I guess he had been caught before, but it was for looking at kids. They also let me know that there is a pretty good chance that this guy recorded me taking a shit, as that is what he was known to do.
Later that night I am at a bar with some friends and I tell them the story. College guys, so they think it's hilarious. And of course, when I walk out of the stall later on, my buddy's standing there rubbing his pants and moaning. Dipshit.