I was actually in a lobby with you not too long ago. I believe it was a HC NC lobby. I don't normally play HC (pretty much Casual and RNG) but none of those were available.
Anywho, what Carcano said has some truth to it. There are some out there that think they shouldn't be killed. I was in a 5 man party a few weeks back and killed the host three times in about a minute. After the 2nd kill I told my team, "Well that's twice inside of about 30 seconds so I'm probably on his list" 15 seconds later I hit him with number 3. That did it...kicked. Nevermind the fact that this guy came back to the same spot all three times inside of 2 minutes scoping for me thru his rifle (and don't get me started on how stupid I think the scope glint is in this game). So I shut down the game and restarted. Joined the same game and I got kicked as soon as I spawned in. Tried to send the guy a message to ask why he kicked me but his message settings wouldn't let me. Tells me he probably does it a lot if he's set up to not receive messages other than from friends. Pretty much the guy Carcano describes. As host, the only time I generally will kick someone is if they have a bad connection that is screwing up everyone else's. Generally the guys with 500+ single red bar ping in a lobby with 200 or less green bar guys. When my target starts teleporting around in and out of my scope and rubber banding, he's gone. Even if it's one of my team.
That and if I know they've kicked me for no good reason in the past. I usually return the favor. I have a list...LOL.