Still, how will the students learn the correct way to do it if no one is calling them on their mistakes? You could go tell the school's director that the flyers were done improperly and explain how they were supposed to do it. If they continue to do this, I would report them, because it IS breach of contract. Even if the students has to suffer and not do any shows for awhile, that's life.
Considering how often my English teacher dragged us into folding programs for her shows back in high school, I think I STILL know most of the basic rules.
Like a firework unexploded
Wanting life but never
knowing how