You’re correct, but it wasn’t standard. The normal rules were the old “your duty to try and escape”, but towards the end of the war (when there was a greater risk of escapees simply being shot) I seem to recall that there was a general message, not rescinding the duty, but suggesting that it was probably a better idea to wait out until the Allies got there by that point.
The whole point of The Great Escape was to make it a Big Deal – and they succeeded. Although they got only a fraction of the men they’d hoped to get out that night (owing to a number of factors, but chiefly because the tunnel emerged not in the woods, as they’d hoped, but out in the open) – 76 rather than the 200 or so they were set to liberate – they tied up the German army quite a bit in tracking down the escapees. Hitler himself issued the “Bullet order” that had fifty of them executed in violation of the Geneva Convention agreements. It was done to dissuade further escapes.
I find it incredibly hard to believe that the “duty to escape” was some sort of holdover from feudal times. It’s an obvious action by the military to not only extend their effectiveness, but to keep up morale. Being in a POW camp was no picnic. As Paul Brickhill (himself a former POW) noted in his book “The great Escape”, life as a POW could be acceptable if a.) you could get enough food to fill your belly for once; b.) the Germans didn’t keep dropping hints that they were going to shoot people; and c.) if it weren’t so indefinite a sentence. These guys didn’t need encouragement to escape – they already had plenty of reason.
Or at least George C. Scott.
In reading the upstream posts, and the summary of Medieval history contained in the link posted by “Little Nemo” above, I am starting to come to the conclusion that you may be right, and there is more to it than that.
If we consider the nature of warfare prior to the Twentieth century, most of the battles were fought with opposing armies facing each other in a big field.
They would hack away at each other until one side decided it had had enough; usually(?) the winner of the battle would be the side with the most men standing at the end.
Given this kind of disposition of forces, if any prisoners were taken, they would be interned within earshot of the battle.
Therefore, it was feasible for them to escape and rejoin the battle; it is possible that rejoined escapees may have some decisive influence on the battle.
Given this, it is logical that some kind of directive would have been issued by the King or Commander to the effect that prisoners were required to escape and come back to the fight.
Over time, this directive would have evolved into: “It is a soldier’s duty to escape”