Exit Poll Problems?

EXIT POLL PROBLEMS?….Andrew Sullivan has a good point:

Doesn’t such heavy early voting somewhat undermine the exit polls? If, in some areas, like Florida, there has been extensive early voting, and most of it skewed Democrat, wouldn’t that make the exit polls look more pro-Bush than the votes might actually be?

I wonder if the networks are taking that into account? They probably are, since (despite what bloggers sometimes think) they aren’t idiots. But it would be nice to know.