A fellow takes a vacation to Las Vegas, A follows B and he finds himself at a brothel out-of-town. He sits down in the foyer and watchs a parade of beautiful women walk past him, coyly smiling. Blondes, brunettes and redheads, short, tall, curvy and gorgous; the guy is pretty stoked, and can't wait to get on with things. The Madam comes out, and leads him upstairs, and knocks on the door of a room.
When the door opens, the guy is agast. Waiting for him, arrayed on the bed, is a seventy year old woman, baggy and saggy, with a toothless grin and evil leer.
"Hey!" says the guy, "I paid you $200! I want one of those other girls!"
"Sorry," says the Madam, "but we are a Union shop, and Doris here has seniority!"