Scrip was used by the military to prevent black marketeers from obtaining American products. Soldiers were not allowed to have US dollars in country and required to exchange all their dollars for scrip when they got in country. Scrip exchange was done to thwart the black marketeers who had amassed scrip illegally by making their scrip worthless, therefore there was never any announcement prior to the exchange, it was a surprise to all including GI's. They closed the gates and made the exchange, so anybody who was outside the gate with scrip lost their money as it was now worthless.
When Charles tells Mr Kim that they will be buying scrip at 10 cents on the dollar, Mr Kim says that this is a 90% profit for Charles. However, it is actually a 900% profit, as for every 10 cents invested, Charles is getting a dollar in value, or 90 cents profit (which is 900% of the initial 10c investment).
There were never any "Mayan Indians" in the Southern Hemisphere, as is asserted in Klinger's West Point exam.
Igor changes the position of his hands on the mess tray (in preparation to throw the tray in Zale's face ) BEFORE Zale gives Igor any reason to feel he's being cheated.
B.J. makes the joke "In Buddha We Trust" about a possible scrip forgery.
However, "In God We Trust" was not on Korean War MPC (scrip). It was also not on U.S. banknotes until 1957 (after the Korean War), when it appeared on $1 silver certificates, then on 1963 series Federal Reserve notes.