Don't confuse people with facts, that will spoil the fun. Schwatz Pferd was the Europe operational counterpart of Robin Sage. The local German population were enthusiastic participants in this exercise for years. They would choose side early on and then played the same role year after year. There was a real world component that was off the radar, but this was the Cold War.
One of the funniest things I ever saw was a boating while intoxicated lesson for some Coast Guard boarding officers. They took some paid role players, provided them with a stocked liquor cabinet in an adjacent classroom and had the Coasties do sobriety tests on them. Pretty hilarious, and valuable.