The mortal sin, then, is using flip folders for pregame, suggesting that the band cannot memorize its own fight song or music it plays every week. Sometimes the use of flip folders is optional and not uniformly enforced, so members using them stick out, brandishing their awkward plastic folios like a scarlet letter. It's like riding a tricycle: Sure, you can brag that you won't tip over, but you really ought to learn to ride a bike. Plus, what happens if you drop it? Now you're lost and hopeless, you owe money to the equipment staff, and you've violated another commandment of Michigan football: Don't trash the Big House!