Apparently when you refuse to party it's an automatic "okay" for them to start KS'ing. I've refused to party many times because 1. I like to solo and 2. because I absolutely hate random party invites without even a "hi".
And this seems to be the case for the Lv20 Abyss. Every time I refuse to party they start kill stealing. The good thing about being an Archer? I get to poison and run... then pull them into more mobs to kill them. xD /evil
I was told to stop running (nub) but... I'm an Archer, it'd be dumb to stand there and let them hit me.