I like the idea on the surface, but my gut tells me that if Michigan is really that close, he does not need to spend money there to win the election. Unless the polls are well-off (negatively for McCain) in the other swing states, I think he would be better focusing exclusively on the states where he has a slim lead and/or have voted Republican lately (e.g. VA, OH, FL, NV, CO). He wins those, and BHO can’t win... I hope he is not wasting money in MI and PA; I just can’t see them going McCain, and if they do, it will be a landslide where national ads would be just as effective.
I think precisely because MI is very close that they put an ad tailored to MI.