Card counting is not illegal anywhere in this country. In fact, it's illegal for it to be illegal in New Jersey, which long ago banned casinos from barring card counters from playing at the blackjack tables. Of course, the A.C. casinos have taken drastic enough countermeasures that card counting there is difficult at best, such as using eight-deck shoes that are shuffled early and prohibiting mid-shoe entry.
While not illegal in Nevada -- as long as you’re not using a device that helps you track the cards -- the casinos are private property. Hence, the owners, bosses, or their representatives have the right to "back off" or "bar" anyone they want to for any reason at all.
When backed off, a blackjack player is asked not to play. In many cases, a player is told that he’s welcome to participate in any game in the casino except blackjack. Barring -- also known as being 86’d, being read the Trespass Act, or being trespassed -- entails a boss or security guard telling a player that he’s not welcome anywhere in the casino ever again. If you’re barred and you return, you can be arrested for trespassing.
Is this discrimination? Card counters have always thought so. However, it doesn’t fit the legal definition of discrimination, since card counters aren’t members of a race, religion, nationality, political affiliation, etc. In other words, they’re not covered by discrimination laws passed by Congress and upheld by the Supreme Court.
Over the years, many card counters have been "backroomed," meaning bosses or security guards have forced them into a room or office away from the casino. There, they grab IDs, take mug shots, and generally intimidate (many card counters, back in the bad old days, were also assaulted). We don’t know of any state in the U.S. where it’s legal for a business establishment to detain a customer, unless he or she has committed a crime and the business representative is making a citizen’s arrest (basically, holding the person until the police arrive). So, in theory, you can be detained if you’re caught cheating, but you cannot be detained for card counting.
That’s not to say it doesn’t occur, though, and several court cases lately have resulted from exactly that happening to blackjack players. Some casinos are tolerant of card counting, especially if the bets aren’t too big and the spreads (the difference in size from one bet to another) aren’t too outrageous. Others are so intolerant of it that they become aggressive in tossing out anyone whom they suspect. This often manifests in their evicting someone who wins even a little money at the 21 tables, counting or not.
Native American casinos are a different story altogether, especially those within reservations. In these situations, the tribe is the law, and the tribal police enforce it. Players have fewer rights, and little recourse after the fact in the case of disputes. The local police won't come, because it's the tribe's land and they have no jurisdiction. You can't sue them either, except in a tribal court. It's touchy.
For those who want to know more about this subject and the down-and-dirty particulars relative to the battle between players and casinos, an excellent new book has just come out. Written by the number-one attorney defending advantage players, Robert Nersesian's Beat the Players is a fascinating account using real-life examples that have been recently litigated.