Guns, would you like to hear it from all the servicemen who ain't in jail?
Fact: Wounded, stunned japanese were routinely killed in the pacific; not at all unusual for a wounded Jap to get a kill shot from a GI. Legal? Nope. Routine? You bet. Successful Japanese surrenders were damn few; more tried than you might think. Some units in Europe operated with a similar policy.. even a formally surrendered german had a 50/50 chance of making it to the rear alive... even less if he was from an SS division.
Vietnam? I know for certain fact that tossing prisoners out of Hueys wasn't just a rumor. And, in a similar disgusting case I seem to recall Lt Calley was pardoned by the President.
War sucks.. especially if yer on the losing side. These days, with imbedded press and cameras everywhere the battlefield is just a little bit less dangerous for a surrendered soldier.. if it's one of theirs. One of ours is likey to get gutted, denutted, and dragged through the streets alive with film at 7:00 on Al Jezzeria.
Heluva world, enh?