One thing I always have and will do is "ask if someone is ok or needs help", with EVERY 1 vs 1 I come across. Some say "If you can stay near and if I lose the adv., come on in". Most say, "Come on in". I don't barge into 1 vs 1's as I enjoy them.
Another thing, I banged the hell out of DH's 109. I noticed him hit the deck and called him a runner as joke. He told me "I'm winchester". I gave him a free pass to rtb. I just don't NEED kills like that, but I notice more and more do need that kill.
Bottom line, some are still courteous.