When a bet is official, the bookmaker has verified that the bettor is of legal age to place wagers and that they are located within the borders of a state where sports betting is legal. The process of verification can take a few minutes or less and is usually conducted by using a photo ID, credit card and/or phone number to ensure that the bettors are who they say they are.

While most states have legalized sports betting, there are still some restrictions on who can bet on what events. Most of these are focused on college sports. In general, collegiate bettors must be at least 21 years old and reside in the state where they are placing their bets. In addition, most legal US betting sites will verify that a bettor is of legal age and location as part of the sign-up process.

The NFL has a strict policy against players betting on their own team. Those caught violating the league’s rules will face indefinite suspension. In order to help keep its athletes safe, the NFL works closely with regulators, sportsbooks and integrity firms. It also beefed up its in-house technology, dedicating security personnel and partnering with companies that provide monitoring services for betting markets.

In 1919, professional gambler Joseph Sullivan paid eight members of the Chicago White Sox (Oscar Felsch, Arnold Gandil, Shoeless Joe Jackson, Fred McMullin, Charles Risberg, George Weaver and Claude Williams) around 10,000 dollars each to fix the World Series. This was one of the biggest gambling scandals in sports history and resulted in a lifetime ban for each player.