Yesterday, the director of Hangover 2, Todd Phillips, announced that Mel Gibson would not be in a cameo for the upcoming Hangover 2. "I thought Mel would have been great in the movie and I had the full backing of Jeff Robinov and his team. But I realize filmmaking is a collaborative effort, and this decision ultimately did not have the full support of my entire cast and crew." It appears that Zach Galifianakis was the driving force behind this decision, so good on Zach.
Deadline says in their post that it is not fair because they do not see what Mel Gibson did to deserve banishment. They also say it is not fair because Mike Tyson is a rapist and he got to be in the first Hangover. That is true and I was not a big fan of that decision and felt they should have left him out. They also said that it is not fair because actors still appear in Roman Polanski films. This is also true, but I think actors who do that are wrong.
Will Mel Gibson ever make it back? Probably. People have very short term memories, but that does not make it right.