An interesting Salerno story I read about in Salerno: a Military Fiasco follows: A medic stumbled out of his landing craft after a several hour ship-to-shore movement. As he to looked to one side he spotted a German machine gunner. The machine gunner pointed to his helmet and then his arm then to the medic (who wore the standard red crosses in the places where the German had indicated on his own uniform.) The German indicated to him to hit the deck; when he did so the gunner began to mow down the troops that were all around the craft. The German was hit shortly there after by some sort of round and was blown apart.
I think it is interesting how when it comes down to following the "rules" of war it often comes down to individual actions of single soldiers. If I check that book out again from the library again I will see if I can't post the word for word acount if I can find it (it's a big book.)