Grosjean specializes in finding vulnerable games like the one in Shawnee. He uses his programming skills to divine the odds in various situations and then develops strategies for exploiting them. Only two questions seemed to temper his confidence in taking on this particular game. How long would they be allowed to play before being asked to leave? How much money would they be able to win? ... Many casino executives despise gamblers like Grosjean. They accuse him of cheating. Yet what he does is entirely legal. ... because regulated casino gambling now takes place in at least 40 states, casinos compete for customers in part by introducing new games, some of which turn out to be vulnerable. ... Common advantage-play techniques include “hole carding,” in which sharp-eyed players profit from careless dealers who unwittingly reveal tiny portions of the cards; “shuffle tracking,” or memorizing strings of cards in order to predict when specific cards will be dealt after they are next shuffled; and counting systems that monitor already dealt cards in order to estimate the value of those that remain in the deck. ... Teams of advantage players — which usually require one person to bet and another to spot dealers’ hole cards (those turned down and not supposed to be seen), track shuffles or count cards — have become so prevalent that they often find themselves in the same casino, at the same time, targeting the same game.