Like many others, I will never boo the players if they're playing their hardest. Obviously, last week they were not. Now, it's at least partially on the coaching staff if the team was looking ahead to USC last week, but everyone, from Brewster down to the waterboy (with the possible exception of Bennett, who was one of the few players who showed up) disgraced the University of Minnesota last Saturday. For that they deserved to booed lustily.
Now, I don't expect the U to win tomorrow. I do expect them to show up and try their damnedest, though. If that happens I would agree booing is improper, for many of the reasons already stated in this thread. But if the game turns into a rout, then vocally expressing one's displeasure is not only proper, but necessary. For all the reasons that others have given to justify booing. Especially if the team gives up, a la 55-0 game vs. Iowa a couple of years ago. While these players are "amateurs", they're being given a $100K free ride to attend one of the best universities in the nation. In return, as an alumnus, a contributor to the U, and a taxpayer, I expect them to give 100% every Saturday. Anything less than that is unacceptable. And if they were giving it all they had last Saturday, then this team is in big trouble tomorrow.