I had a doc's appointment, he had a few spare minutes, and we talked a bit. He mentioning knowing a fellow in his 90s who'd been, in WWII, a POW--he was a German, and was in the POW camp in the US. He said that "Hogan's Heroes" was modeled on their experiences, with roles reversed so that the German prisoners were Americans. The guards got pretty friendly after a time, and didn't mind if the POWs sneaked off into town so long as they returned. The POWs were happy, good food rations, no risk of getting shot up. The only escapes came after the end of the war, when they were to be repatriated. They got letters from home telling how the place had been bombed and destroyed, hunger was rampant, the economy was nonexistent, and in his case, he would be set to East Germany, looted by the USSR and under communist rule.
He and others chose that time to escape. They'd learned a good deal of English, and just blended in. Eventually he married an American, had children, became naturalized, and settled down.