The business model for casinos always includes the simple idea that in general, gamblers will lose more than they win. Every game is constructed to fulfill that expectation, while still allowing enough winnings to keep hopeful gamblers interested. Any factor that alters those odds, therefore, threatens the casino business.
It isn’t illegal to count cards when playing blackjack, even though knowing what’s left in the deck gives you a considerable advantage. There isn’t any way to prove what’s going on in the gambler’s head (at least, not yet) – though if he or she is suspected of card counting, they’d probably be asked to leave.
On the other hand, using a device to aid you in counting cards is a felony in Nevada (gives you an idea of how much the gambling industry means to that state’s economy, eh?). If discovered, casino operators are given the latitude to decide whether to hand you over to authorities or deal with you in their own (gulp) way.
The Nevada Gaming Control Board has sent out a warning to casinos about a new IPhone app by TMSoft called Card Counter. They were tipped off by California gaming authorities, who were in turn notified of the app by operators of an Indian Casino in the northern part of the state. Supposedly, this app can be used to count cards during a game, and can even be operated in “stealth mode” with the screen off. If you know where the right keys are, I guess you can hold it in your pocket and avoid detection.
The app is available through iTunes. Its description there and on the TMSoft site says a lot about how it can teach you the strategies for card-counting, but nothing about being able to use the app as a card-counting aid while gambling.