Mr. Monk and His Biggest Fan - S6-E1
Plot hole: It's out of character for Monk, a chronic stickler for details, not to correct an error, especially one relating to his own life. Marcy's diorama for "Mr. Monk & the Three Pies" includes Natalie, who wasn't around yet when "Three Pies" occurred. The doll should be of Sharona, but since that would ruin the ensuing joke, Monk is allowed to overlook it. He's aware of Marcy's unreasoning obsessions, but Monk's OCD would simply not permit him to keep quiet about a mistake that glaring.
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