Fans shouldn't be throwing stuff at players.
Players shouldn't go running into the stands after random fans who are mouthing off.
If I was sitting at work, in a workplace with surveilance, and someone throws something at me from the row of cubicles behind me I would probably get the police to go find who did it. Defending myself does not give me the right to go over to that row of cubicles and beat up some guy who's laughing at me for getting hit with a water bottle - as much of an ass as that guy might be.
I thought Jackson was even worse, he wasn't even involved in the original altercation or when Artest got hit by the cup, he just ran up and threw the first punch.
Bottom line, everyone involved was at fault.
Sums it up well:
http://sports.espn.go.com/nba/columns/story?columnist=ratto_ray&id=1927360 
