Mr. Monk Goes to Mexico - S2-E2
Factual error: Monk states that one of the reasons he suspected Dr. Maduro was because the doctor stated the amount of fluid in the victim's lungs in pints, which meant the doctor had worked in the US. But even in the US, the medical profession uses the metric system.
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