Is Mitt channeling Bush?

Last night in the Rebuplican debate Willard "Mitt" Romney was asked about Reagan. Just before he answers an audile "raise taxes" was heard. I was on Crooks and Liars live blog and a lot of people heard it. Check the open thread to see people discussing it. You have to scroll to around post #431. Do all the candidates get surrogate speech writers in the middle of a debate? Mitt is a fool.