Let's say he's a good distance away for you to get your knife out and get prepared, no other enemies or friendlies around, and it clearly looks like he wants to have a knife fight
I'm a pretty honorable guy when it comes to knifing and I would agree to have the fight instead of shooting him/her down... Unless your name is Dom po po and you are waiting in the shadows to stab me in the back on Italy.. yeah bullet in the head for sure
Yeah, I agree with Krisis. Unless some ninja managed to sneak up right to my face, I pull out the infamous knife and try to shank the guy. If he pulled a ninja on me, I have to shoot, because otherwise I'd pee myself or have some other undesirable reflex.
Recently, especially on Italy, I've seen people fake a knife fight then pull out a gun and shoot. If I find you, I'm going to knife you then stone you to death. Consider this a warning.
This is a hard one - I shoot, but not for an easy kill. It's just a reflex thing, an enemy is an enemy. I honestly would do knife fights if I could, but I take no chances on getting myself shot