The two drivers wrecked in practice and then carried it into the NASCAR officials' trailer. It's widely believed that Stewart punched Busch but no one will confirm or deny the speculation.
A NASCAR spokesman says the two were disciplined solely for the on-track portion of their clash, when the drivers deliberately used their cars as battering rams.
NASCAR officials came into this season saying drivers would be given more latitude to show emotion this year, and the relatively light nature of today's punishments would seem to support that.

http://accesswdun.com/article/2008/2/206916