"Vacation Time" joke

Joan, the rather well-proportioned secretary, spent almost all of
her vacation sunbathing on the roof of her hotel. She wore a bathing suit
the frist day, but on the second, 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 Hilton doesn't
mind your sunbathing on the roof, but we would very much appreciate your
wearing a bathing suit as you did yesterday."
"What difference does it make," Joan asked rather calmly. "No one
can see me up here, and besides, I'm covered with a towel."
"Indeed," said the man, "but we would prefer you didn't lie on
the dining room skylight."
-Roger