Continuity mistake: When Leigh Anne goes downstairs to see Michael after the first night he stays with the family she is wearing a simple gold cross necklace. When she has to catch up with Mike out on the driveway she is wearing a cross make up of round diamonds. The two necklaces change appearance in same scenes in several places.
Character mistake: In the scene where the biology teacher (Mrs. Boswell), looks-over Michael's test paper. There are at least 4 or more factual, spelling, and/or grammar errors on the test itself: Question 5, answer "a" has incorrect grammar. Question 6, uses the spelling of the number 2, as "to". Page 2 of the test, question 3 spells the number "two" incorrectly. Question 4 refers to a previous question about environmental changes that doesn't exist in the test.
Character mistake: During the montage of teachers trying to get Michael up to speed, we see a history test Michael has completed being marked. The question at the top asks where the battle of Waterloo took place. Michael has answered Germany, which has been marked by the teacher as correct. The correct answer was actually answer C, south of Brussels.