Factual error: In the scene immediately following Harry and Hermione's travel back through time, she tells him, "It's 7:30." The clock, however, is striking the bells for an hour, not a half-hour. (01:43:45)
Factual error: When Harry is beating up Malfoy and the two Slytherin boys in front of the Shrieking Shack, he grabs one of them by his scarf and rotates him around. The center of their revolutions should be at the end of the scarf (where Harry grabs it), but as there is no actual counterweight for the boy he has to balance only his own body, which moves the center of his revolution strongly towards him. (01:00:10)
Chosen answer: Fred and George used the map to aid them in their mischievous activities at Hogwarts, and probably had little interest in what their little brother was doing or who he might be with at any given time.
raywest ★