Mr. Monk and the Genius - S7-E2
Revealing mistake: While Linda is lying dead on her bed, you can see that she is breathing, in two cut scenes, especially at the moment when Monk says "I don't know."
Revealing mistake: When Cassie Drake pushes Joseph Moody down the stairs, it is very obvious that the man falling down the stairs is not Jack Carter. His hair is not even close to the same color.
Mr. Monk Gets Hypnotized - S7-E8
Revealing mistake: There is an obvious stunt double when Monk is fighting with Sally Larkin for the piece of chewing gum: he is younger, more tanned, and possibly wearing a wig in order to emulate Tony Shalhoub's hair. (00:35:55 - 00:39:05)
Mr. Monk Makes the Playoffs - S7-E13
Revealing mistake: When Monk steps in front of the limo to stop it from leaving, on the bottom right of the screen there's a black line that doglegs to the right (seen over Monk's coat sleeve). It's like the camera was cracked or something was stuck to it. When the camera angle changes it's gone, but is there where the camera is back on Monk.
Mr. Monk's Other Brother - S7-E10
Revealing mistake: When Reese opens fire on Adrian, Jack and Natalie at his house, in a shot from Reese's perspective, the squibs from bullet hits on the ground appear to be below the barrel's trajectory. The bullets should be hitting the ground closer to his targets' feet.
Mr. Monk Makes the Playoffs - S7-E13
Revealing mistake: 7-13, "Mr. Monk Makes the Playoffs": The supposedly live stadium crowd outside Bob Costas' press box is a noticeably fake photo-backdrop. Not a single "person" in the multitude of thousands is moving. (00:40:10)
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