Charlie Gibson plays gotcha with Palin then plays dumb on Acorn story?

You know, Gibson comes off as a know it all pompous azz interviewing Sarah Palin but when someone asks him about a major national story (e.g. Acorn videos, census boots Acorn, US senate cuts off Acorn funding), a story someone in his profession at his level should be well informed about, he says he hasn't heard of it??? Does this mean he's an imbecile and SNL will be doing skits on him?