The irony was that that character (I believe it was Flt. Lt. MacDonald) had previously criticized another escapee during training for making the same mistake.
I love this exchange between Brosnan and Colburn:
In regard to the OP, there’s this recent thread on the same issue. I posed a doubt similar to the OP.
I don’t know if it has had anything to do with catching spies, but I’ve heard that the habit of keeping ones hand in ones pockets is itself an Americanism.
Another problem with tis story is that in all my reading on the subject, I’ve never seen reference to OSS or SOE sending more than a handful of US or Commonwealth spies to Germany. There were spies there, but mostly recruited from within German society. OSS and SOE teams were much more active in Occupied Europe, France especially. They would have to pass as Frenchmen, Czechs, or Dutch, where such subtleties as regional accents are less important; the Gestapo officer isn’t likely to know it themselves.
the safest disguise (frequently used by PoW) was a foreign worker, of whom many thousands were in Germany, voluntarily or otherwise. This would account for the accented German.