Yeah, but if 25% of votes are cast before election day, you've gotta believe the campaigns will find a way to model those results; that data's too valuable.
I'm sure they do exit polling but that would be tempered
to whomever is doing the exit polling.
The parties poll the early voters and absentee voters just like they do the likely voters. So they probably do have a statistically correct idea of who is leading among absentees and early voters.
I work for an elections department in Florida and I can tell you first hand, there are no campaign personnel or any of the pollwatchers , solicitors, etc that are anywhere near any of our early voting votes or absentee ballots. All we can give out as information is what party the person who voted is--that does that mean if someone is a democrat, they voted democrat! This is a very loose assumption if that's what the media is promoting. No votes will be known until 7pm election night when the precincts start uploading the results.