Yes (under stall)

Quietly approaching the stall, you kneel down, looking through the sizable crack between stall door and floor. Surprisingly, you see not one but two pairs of shoes. Being so close, the sounds are clear--they're moaning. A guttural, dominant, growl, and a weaker and yet still decidedly masculine, subby moan. So there are people having sex in there.

You jerk your head away in shock. Thankfully, they seem to not have noticed you. They're to absorbed in each other's company, you suppose.