I got a warning on my account because I got pissed at some jackasses appearing out of nowhere to fell cleave the 10 mandies I collected with Diaga, so next pull I called for help on each on and apparently 'stole' a yellow mob that was agrod by a ranged attack by an automaton belonging to that same group of jackasses, killing them with Blaze Spikes and regular melee. Only did that on a single pull. With plenty of mobs left of them to kill.
I've never seen a GM respond that fast, so I can only assume some GMs are not fair and impartial when their 'friends' are inconvenienced...
Good luck trying to complain about it though... Customer Support tells you to contact ingame GMs, ingame GMs send you an auto-reply to contact CS...