Mr. Monk Takes Manhattan - S3-E1
Trivia: When Monk is playing the 'find the queen' game with the crooked busker, one of the onlookers is Andy Breckman, the show's creator. He can be seen smiling in a close-up shot of him after Monk wins a second time. He has glasses, a beard and moustache, and is bald on top.
Answer: The two men are trying to work out a secret deal between them without involving the union, which means the workers' interests aren't being represented and defeats the whole purpose of a union. The mayor would lose labor's support and Cusack's union troubles would just be starting.
Captain Defenestrator