Kind of. Once at uni I got into a bathroom stall with a gloryhole by accident. On the other side was a guy who looked trough looked trough the whole. I 'm pretty sure he was fapping. Didn't take advantage of the situation at the time. Not sure if I would now.
I have also so been in public bathrooms were there is cum all over the toilet seat.
I'm not exactly a prude, but IMO exposing unsuspecting people to sexual acts is not really okey. Uh, it does turn me on, though.