She will upstage him. She will cast her (perceived) ignorant stink all over the convention. All people will be talking about "Palin got double the ratings of Romney". It'd be like MSNBC having their own campaign saying "Why can't Bill Clinton speak at Obama's convention?"
Panelist Michelle Fields of The Daily Caller claimed that the Romney people don’t want Palin because she will outshine Romney, and Bill O’Reilly offered the most crackpot solution ever.
O’Reilly said, “You can give the governor of Alaska a platform on a day that Mitt Romney isn’t speaking. You could have her rally the tea party folks who adore her, and what’s the downside of that? They don’t even have to see each other really.”