Apparently director Todd Phillips was going to put in a Mel Gibson cameo and the studio was okay with it, but some of the "cast and crew" hadenough of a problem with it that Phillips dropped the idea.
(How many of them had a problem with the extended cameo from convicted rapist Mike Tyson in the first film?)
Gibson's been engaging in some pretty indefensible behavior lately. I'd like to see the guy find redemption. Gibson making fun of himself in Hangover 2 sounded like a good idea. Oh well.