"The brothel makes us strong" joke

A dedicated shop steward was at a convention in Las Vegas and decided
to check out the local brothels.
When he got to the first one, he asked the madame, "Is this
a union house?"
"No, I'm sorry it isn't."
"Well, if I pay you $100, what cut do the girls get?"
"The house gets $80 and the girls get $20."
Mightily offended at such unfair dealings, the man stomped
off down the street in search of a more equitable shop.
His search continued as long as you want to draw things out,
until finally he reached a brothel where the madame said, "Why yes,
this is a union house."
"And if I pay you $100, what cut do the girls get?"
"The girls get $80 and the house gets $20."
"That's more like it!" the man said. He looked around the
room and pointed to a stunningly attractive redhead. "I'd like her
for the night."
"I'm sure you would, sir," said the madame, gesturing to a
fat fifty-year-old woman in the corner, "but Ethel here has seniority."