Possibly the most notorious incident of this kind in my experience occured at a festival in the mid 90s. He had the only "camper" in the group - the rest of us were all tenters - making identification of the source quite simple.

A description of the "activity" would be difficult; but it probably is necessary only to note that for about a half dozen years thereafter some 3 or 4 hundred people "back home" knew exactly who you meant when you made reference to "Lassie."

John