Haha! That happened to my sister!
-Anyways, my sim was in Al Simahara and she was tired (instead of buying a tent, I bough sleeping bag at home.) So I placed her sleeping bag on the floor and used the option 'Sleep' so she is calmly walking there when out of no where (She was in the middle of the dessert.) Some random guy appears and, eh, goes to sleep on her sleeping bag. Somewhat.