Went to Waterloo, ON area about a year ago to visit my wife's cousins. Took them out for a GEOCACHING training run to show them HOW it's done and what to expect. It was early spring, but a very warm day. We were heading along a paved path near a river and just as we got close to the bridge to cross, (we had 5 kids with us, me, the wife, her cousin D) I'm looking ahead to see how the trail is going to when I see WHITE movement to my left. Two white things, round, globular looking with a black strip between them. They were moving up and down. Then we heard the moaning and panting. Quick turnaround of the whole gang "RETREAT RETREAT" UH, WRONG WAY, WRONG CACHE, sorry...back where we came from. Yeah, a young amorous couple, with HER in the dominant position, going at it right on the riverbank, oblivious to what was going on around them. (nice black thong)
To this day, D always mentions it when we say we have been caching, and he tells others that "you'll NEVER know what to expect when you go caching". I think it actually scared him to not bother with it yet, although it has to be a one in a million kind of thing.
As we left the area, another couple with a blanket was quickly hiking into another trail with a couple of sly smiles on their faces, no GPS, hiking boots or printed pieces of white paper. ;-)