Seem to get quite a few cases of hitting someone, then they hit you and they don't take the hit because they "hit you first"
I personally take the hit even if they get hit with their gun lowered, then aim and shoot me. I do normally say do you want to take your hit as well, makes some people realise whilst I guess others like cheating...
Whilst I can see why some people think going down the overkill route is a good idea it certainly isn't going to improve gameplay, much like screaming take your hits at the top of your lungs won't.