It was a new club, and its logo was being designed. The first draft came back misspelled. But club members couldn't agree what the correct spelling was.
Group A said it was "The Cousins Club." They said "cousins" was an attributive adjective.
Group B said it was "The Cousins' Club." To them, "cousins'" was a plural possessive adjective.
Group C said it was "The Cousin's Club." They couldn't name the specific part of speech, and during the discussion demonstrated that apostrophe's belong in lot's of place's.
The club did not survive this disagreement. I believe they did get the logo designed, but there were enough hurt feelings from the discussion that all the original momentum was lost.
“The company returned to private ownership in 1916, when all shares were purchased by Roderick Jones and Mark Napier; they renamed the company "Reuters Limited", dropping the apostrophe.”
One feels for the cousins who didn't care about the punctuation or its absence, and simply wanted to gather.