Who cares if Artest was egged on? You don't jump into the stands to fight. But Artest is a showman and an agitator. By laying on the scoretable, he was trying to incite a eaction.
Now of course, there's no way I can say what you would do...because, well, I'm not you, but do you not believe that you would do the same thing in this sort of situation? As an example (this would probaly make it more clear..seeing as most of us probaly wouldn't have the decision of whether or not to run in a crowd at a pro basketball game) but anyways, as an example, if you were in a club...and there's a VIP section..that you aren't in, but someone that is in the VIP section throws something at you purposely and it hits you dead in the face. Are you just gonna stand back and look at them angrily, because rules say you can't go in the VIP section?...You might say yes, but I know for sure, the better part of..well, anyone wouldn't stand for that and they'd run right for that person ready to fight. IMO...this is no different.