Disclaimer: I am NOT looking past the Va. Tech game, and I don't automatically assume that NU will win that one. But here are my thoughts, for what they are worth.
I think (and this may be a conspiracy theory) that NU, if they beat Va Tech by a couple of scores, will be ranked going into the Mizzou game.
It's like how the Huskers were ranked going into the USC game last year... they didn't deserve it, but since it was early in the season and nobody really knew, the polls put NU up there to make it a "must see" game.
Mizzou has the kind of national attention that makes people look a little harder at their opponents. People will take a good look at Nebraska, especially Bo, and (intentionally or not) make the game a big event.
If the Huskers lose to the Hokies, none of that matters. But if the Hokies limp away from that game after being embarrassed in Lincoln, look for NU in the top 25.
The way I see it, polls don't mean much until mid-October, except for the TV ratings.