An enemy capturing a soldier with a rifle marked with his girlfriends name or something personal like that wouldn't incur their wrath. But to have those notches or swastikas or an enemy soldiers wristwatch etc etc would bring on the pains, believe me. It is the very FIRST thing that you are taught in real life but, alas, not in the popular comic books relating to snipers.
Those swastikas are the only thing that I don't believe to be correct about the rifle.