In the DVD commentary, director David Mirkin states that being a native New Yorker, Sigourney Weaver did not know how to drive, which made her extremely nervous during her driving scenes in the film.
The card handling that Jennifer Love Hewitt does in the restaurant (saying it relaxes her) was taught to her by stage magician Ricky Jay. She actually learned more tricks than that, but was unable to do them in the movie because she broke her finger. Ricky Jay plays the auctioneer in the film and is also in the credits as "technical adviser : con games."
The most expensive shot in the movie was when Jennifer Love Hewitt leaned against the car to talk to Ray Liotta near the end of the movie. Because it was cold on set, she had a white sweatshirt around her waist that was in the shot, and it had to be digitally taken out.