Go Light on the Heavy Water - S1-E9
Continuity mistake: The boys are looking out the window at the mysterious truck. When the camera looks at them from behind, there's a building right in front of them.
Go Light on the Heavy Water - S1-E9
Continuity mistake: When the smoke bomb goes off, Klink has his monocle on. After the smoke really starts, his monocle is gone without being taken off.
Answer: It's a comedy, not a documentary.
stiiggy
Perhaps it was counterfeit. There are numerous episodes where they deal in counterfeit monies.