Character mistake: In the scene where Sam is filling out the confidential questionnaire, the word "confidential" is spelled "confidentail".
Character mistake: The map has the word Corazon missing the accent: "Corazón". This is so basic grammar that maybe it was done on purpose.
Character mistake: In the beginning of the movie everyone shows up on Monday. When Rosenberg is taking attendance he mispronounces the girl's name. She corrects him and he says yesterday and the day before it was something else. That would mean they came to school Sunday and Saturday.
Character mistake: The ref says there's no rules before McClure fights Whiplash but she tries stopping them later.