prologos
That story is a product of the imagination of a revisionist historian.
http://en.wikipedia.org/wiki/Other_Losses
German POW's that were shipped back to the states in large numbers. Many of them found life as a POW here better than that of a "free" person back in Germany. It was not uncommon for them to march out of the camps to go to work unguarded - we knew they'd come back at night rather than risk a firing squad for escaping.
http://en.wikipedia.org/wiki/German_prisoners_of_war_in_the_United_States