I'm sure there'd be plenty of "butts" in the seats whether the Gophers are in the night game or not. First off, more people from around the state would make the drive for a single game if it was at night. If UMD/UND is in the Friday afternoon game, you won't get many people driving down for it. Put them at night, though, and more people would head down to the game and try to get tickets from scalpers.
The biggest problem is that all those Gopher fans that buy the five game package will only go to see the Gophers play and no one else. Hence, more empty seats than there should be.