Character mistake: In the scene where Sam is filling out the confidential questionnaire, the word "confidential" is spelled "confidentail".
Character mistake: When Hobbs was at bat for the game winning HR, the base runners were focused solely on Hobbs instead of the pitcher, who could have thrown out either. This was the Majors, not Little League.
Character mistake: When on the phone to the police officer Sgt Halloran, noodles calls him Aiello. Danny Aiello is the real name of the actor.
Suggested correction: In the scene you're referring to, the person Noodles calls, and the character Danny Aiello plays, was the police chief, not Sgt Halloran. In the film, Danny Aiello is credited as Police Chief Aiello. Also, his wife (played by Karen Shallo) is credited as Mrs. Aiello.
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.