There is a difference between clearing someones six and jumping in on a 1v1 for a pick. Both of course have in common that your getting an easy kill, given slightly harder then a vulch but not much. Big messy furball and your clearing someones six fair enough, coming across a 1v1 and you drop in for a easy pick is cheap. Especially if you have a rough idea who the con is, and that happens a lot when flying off peek.
If it's a known pilot I even let them rtb if they are on the deck and low on E simply because I have no interest in a easy kill on someone I know. Now if I see a certain Pony around I won't, simply because I still owe you for the cheap pick you did on me few days back when I was mixed up vs four and had just killed the 2nd con. 
<S>...-Gixer
I'm sure it wasn't a 1v1 when I killed BE. It was probably with multiple planes from both sides. If it's 1v1, I will ask my teammate if he needs help before entering.
Was I one of the 4? Usually, I'll not bother if there is already a pile on a single guy. In fact I usually taunt them on range vox. Something like:
"Hey, there's 6 of you on that smoking corsair with the missing wingtip. Do you guys think you can handle him?"

Or was it that time that it looked like they were never going to kill you?
I'll always let a friend rtb if they call bingo. If they don't call but it's obvious they are leaving, I'll ask on 200. No response, I'll probably run them down.
As for picking me. Well I deserve it. In a furball I'll take the biggest threat and kill it. If I miss I usually have a second or third plane in mind as an alternate target. This means people get picked, although I never understood why killin anyone in a furball could be considered picking... it's a furball.