If a casino patron in Nevada is suspected of being a card counter, the management can order them to leave the casino. If the patron refuses or comes back, they can then be cited or arrested for violating Nevada trespass law. Some notorious card counters have been banned from most of Nevada's casinos.
Nevada trespass law makes it a crime to go on or stay on another's property without their consent. In Nevada, trespass arrests often take place in casinos when rowdy customers are asked to leave and they refuse, or when they leave but then come back to retrieve their belongings in their hotel room. Security guards who detain patrons for trespass elect whether to call an officer to arrest them or else to have them summoned to court without them having to go to jail first.
Violating Nevada trespass law is a misdemeanor, carrying up to six months in jail and/or a fine of up to $1,000. However, it's rare for judges to order jail time unless the person is a repeat offender. And if it's a person's first offense, the prosecutor is usually willing to dismiss the case in exchange for a fine. (Read our related article, "How can I be arrested for trespass in Nevada?')