Since I live in New York City and love the Thomas Crown movie, I thought I'd point out the most obvious mistake to some. But to the movie producers, the only solution.....When Dennis Leary or Thomas Crown walk into the lobby of the Metropolitan - it isn't the Metropolitan. It's the NY public library on 42nd street!
That is because it is NOT the Metropolitan Museum of Art. While the intro places us geographically there, MMA would not allow the crew to film there. They couldn't stop exterior filming (and the exterior banner change throughout the film). But you will notice on the security uniforms, etc., that technically this film takes place at a (technically) fictitional art museum. The director addresses this in the DVD commentary.