"In pre-production, the producers and the book's original writers predicted that the Vegas casinos would be unhelpful, as a film that told viewers the basics of card counting might hurt their bottom line. A featurette included with the DVD completely and accurately describes the "Hi-Lo" system used by the MIT Blackjack Club and by Rosa's team in the film.
In fact, the writers were surprised when told by the producers that MGM Studios would finance the film, though all "MGM" casinos (including one used by the real MIT Blackjack Team) are owned by MGM Mirage and are no longer related to MGM Studios. In reality, as another DVD featurette reveals, the casinos (including MGM Mirage) saw the film as an attention-getter; people who saw it would be encouraged to go to Vegas and play, attempting to count cards, when in reality the film withheld critical details (such as the conversion from the "base count" to a "true count"), and in any case, although the counting system is simple, it is more difficult to successfully make money at counting cards than the film portrays."