Other mistake: When Brando, Norton and DeNiro are at the table, DeNiro accepts the job and tells Norton the stipulations. When they first begin talking the ashtray on the table is empty, but when Norton is telling his story there is a book of matches in the ashtray, then later they are gone again. Notice, none of the three characters smokes.
The Score (2001)
1 other mistake - chronological order
Directed by: Frank Oz
Starring: Robert De Niro, Edward Norton, Angela Bassett, Marlon Brando
Factual error: When Nick navigates through the sewer system, he checks his position using GPS. The position on his display corresponds to the middle of the North Atlantic instead of the Montreal area.
Trivia: Most of the conversations between Robert De Niro and Marlon Brando are improvised.
Question: Why does Norton lie and say that he "has company" and then make De Niro wait longer during the robbery? Sure, Norton double crosses him later, but wouldn't making his partner wait put both of them in danger of getting caught since it delays them and increases their chances of getting caught?
Answer: Norton already has an advance plan to prevent himself from getting caught. The delay is both to fluster DeNiro, and to prevent him from having enough time at the moment of the double-cross to come up with an alternate to handing over the prize without getting caught himself.
Rooster of Doom