Other mistake: The two cappucinos that Will brings back to the bookshop, which are then consumed during conversation, are obviously empty cups. The supposedly hot drinks are gone within seconds with no residue on the drinkers' faces.
Other mistake: When the student body presidential candidates are giving their speeches, "Monarchs" is on the Gym floor, and not "Wolverines." This is because the school where it was filmed, Papillion-LaVista, their mascot is Monarchs.
Other mistake: Tony Clifton comes on the 'Taxi' stage accompanied by two prostitutes. He introduces one as Melonia, squeezes her breasts and asks 'how is our produce department?' The German subtitles read 'production department'. (00:44:25)
Other mistake: When Porter cuts the fuel line on the car and is about to light it, Carter's henchmen see him and act surprised. Despite having ample time to get out (as any rational person might do), they just sit in the car and wait for it to explode.
Other mistake: When Carol says, "I've always wanted to try soup but there's the fear of drowning," read Deuce's lips. Hes saying her line along with her.