Sunbathing

A rather well-proportioned young lady spent almost all of her vacation sunbathing on the roof of the hotel. She wore a bathing suit the first day, but, on the second, being a naturist, she decided that no one could see her way up there, and she slipped out of it for an overall tan.
She’d hardly begun when she heard someone running up the stairs. She was lying on her stomach, so she just pulled a towel over her rear.
“Excuse me, miss,” said the flustered little assistant manager of the hotel, out of breath from running up the stairs. “The hotel doesn’t mind you sunbathing on the roof, but we would very much appreciate you wearing a bathing suit as you did yesterday.”
“What difference does it make?” the woman asked rather calmly. “No one can see me up here.”
“Not exactly,” said the embarrassed little man. “You’re lying on the dining room skylight.”