Mr. Monk and the 12th Man - S2-E9
Other mistake: In the scene where Mr.Babcock is murdering the woman in the cinema, we see the woman has a big bucket of popcorn. As he starts strangling her, only a small amount of popcorn falls out. When the camera turns toward the floor there is a lot more popcorn on the floor and it it is spread right across the screen.
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