Not much effect, I think. His personal appearances aren’t that important anymore, they were much more important before people had a chance to figure out who he was. Now, I figure the greatest portion of that is over, and the deciding part doesn’t require more of the same input, he’s not likely to drop a game-changer bomb when he’s winning.
And the McCainanites can’t get too agressive, one, it wouldn’t look good, and two, they don’t have the money. The clock runs, nothing changes much, good for Obama. Much bigger risk in not going, being seen as cravenly ambitious, callously ignoring his dying granny.