You know, Athene, the guy who was the first to level to 79 (he would have been first to 80), but then got banned, asked a GM if it was ok to power level out of group. The GM said, sure. But if Athene had told him the whole store of:
Yes, I'm leveling out of group
But it's in an instance
and I'm dropping group, tagging all the stuff, then having the group kill stuff, so I get full exp
then I'm getting invited back within 60 seconds
so that I get full instance exp.

The GM could have most certainly set him straight.

But he just said 'Is it okay to power level out of group', which was true, but not the whole truth. And it cost him and a bunch of his friends, their accounts.