Everyone Has a Brother-in-Law - S2-E23
Continuity mistake: Hogan is reading the note from the underground on the clipboard that Newkirk brought in. When done reading, Hogan is holding the board at waist height. In the close up, it's suddenly chest height.
Answer: It's a comedy, not a documentary.
stiiggy
Perhaps it was counterfeit. There are numerous episodes where they deal in counterfeit monies.