From Wikipedia: "A prisoner was frequently warned that, unless he could produce information beyond name, rank, and serial number, such as the name of his unit a

From Wikipedia: "A prisoner was frequently warned that, unless he could produce information beyond name, rank, and serial number, such as the name of his unit and airbase, the Luftwaffe would have no choice but to assume he was a spy and turn him over to the Gestapo for questioning. For Scharff, this technique apparently worked quite well. In addition to initially preying upon his prisoner's fears of the infamous Gestapo, he portrayed himself as their closest ally in their predicament, telling them that while he would like nothing more than to see them safely deposited in a POW camp; his hands, he claimed, were tied unless the prisoner gave him the few details that he requested to help him properly identify the prisoner as a true POW." So we have a "good cop, bad cop" technique, not just pure kindness.