Most people turn to water and painkillers after a rough night of drinking. Mark Johnston turned to the courts. The California businessman is claiming he shouldn’t have to pay the Downtown Grand $500,000 he lost gambling during Super Bowl weekend because, he says, he was blackout drunk. And Johnston, 52, has doubled down: Not only did he put stop orders on his markers, he’s suing the property for continuing to serve him drinks.

The whole thing seems a bit ludicrous in a city where the de facto rule is drink, gamble, rinse, repeat. Until, that is, you stop to consider Nevada law, which states casinos are prohibited from allowing drunk patrons to gamble. In fact, Johnston is hardly the first to test the law in court. Terrance Watanabe, who refused to pay $15 million of $127 million in gambling losses at Caesars Palace and the Rio in 2007, filed a civil suit claiming, among other things, that casino employees provided him with alcohol rendering him “utterly intoxicated and unfit to gamble.” (In 2010, both sides reached a confidential settlement.)

How well—or poorly—casinos monitor alcohol consumption depends on their employees. A spokesperson for a major Vegas resort company, who declined to be identified, says, “Security, bartender, cocktail waitress and floor manager all have responsibility to identify” clearly inebriated customers. Dealers? Not as much. Joel Lauer, president of the PCI Dealer School, says it has “no set policy” on educating students about alcohol awareness, although he does try to prepare them. Still, “the dealer is not typically the one to handle the situations that may arise.” (Johnston lost playing blackjack and pai gow, dealer-based games.)

Joe Intiso, a Strip bartender, says anyone who works with alcohol in Vegas has to obtain a Techniques of Alcohol Management (TAM) card, which carries with it four to five hours of alcohol awareness education. But he added that black-and-white education gets a bit gray in the real world, where even the drunkest guests can hide their blotto-ness or wander from table to table, making it difficult to monitor consumption. And this being Vegas, many bartenders “are going to bend the rules and do things they shouldn’t,” Intiso says. “Vegas is going to overserve. Vegas wants you to drink. We want you to gamble and spend money.”