In *Battleground Prussia* Prit Buttar includes a chapter on the infamous sinking of the *Wilhelm Gustloff* in 1945. The author notes that the ship's captain, a Friedrich Petersen, had been captured by the British at the beginning of the war

> but then repatriated to Germany because he was aged 66, on the condition that he did not command a ship again

A little later the author describes how in the panic of the retreat from the Red Army the the authorities were forced to use the *Gustloff* (which had seemed unlikely to put to sea again) in emergency duties ferrying refugees westwards, with Petersen thus 

> breaching his parole


It's possible that Petersen age was crucial, nevertheless was it normal for the Allies to impose conditions when repatriating German POWs? Did they have any way of policing such conditions?

It's clearly suggested that if it hadn't been for the chaotic and disintegrating situation in Germany Petersen wouldn't have put to sea and the British demands would have been honoured. Is "parole" a word the parties would have used and understood in 1945 or is it Buttar's terminology? *Did* Nazi Germany habitually honour such conditions?