Factual error: The cover of the plan for Unternehmen Hannibal is marked "SEHR GEHEIM." That phrasing does not exist in German. The correct term would be "streng geheim".
Continuity mistake: As Newkirk says he volunteers, he straightens to attention, hands by his sides. A second later, his hands are in front" holding a bit of laundry.
Continuity mistake: At the end, while Hogan and Klink are talking, Hogan's right arm alternates between being up with a note in hand to down at his side between shots.
Revealing mistake: While talking about Von Baler's daughter, Hogan is facing the building talking with Carter and Newkirk. Behind him is an open area of the camp. If you look, you can see that there is no guard in The Tower, no shadow of The Tower of the guard hut (the sun is behind them and Hogan), and the snow is piled up about three feet behind Hogan, suggesting that the background is a wall mural in the studio.
Answer: It's a comedy, not a documentary.
stiiggy
Perhaps it was counterfeit. There are numerous episodes where they deal in counterfeit monies.