There are stories of a secluded sunbathing and swimming spot somewhere in the greater Charlottesville area, that is periodically used by students from the University of Virginia, and where the usual attire is birthday suits. It’s said to be a difficult place to find unless you’re willing to do a lot of back-road hiking or mountain biking. But, you can get a clear view of the place from the regional Amtrak passenger train, if you know exactly where and when to look. And even then, there may not be anyone there. But stories say that one time the driver of the Capitol Limited saw a bunch of shapely college girls sunbathing, and a bunch of hard bodied college guys playing a water sport in the river, and he blasted the horn. (As a sign of appreciation or approval?) The students supposedly waved back (not much point in hiding by then), and many of the train riders got a nice thrill. (Given the general prudishness of the USA, I suspect many were also horrified, but that’s another story.) Whenever that train passed that spot again, it would sound out to any revelers who happened to be there. According to some, it still happens.
Personally, I think it’s an urban legend. But something like it would be fun to include in a model or simulation.