3 Card Monty (or similar derivatives)
Hustlers will set up shop on pedestrian walkways offering tourists the opportunity to double their money if they’re able to identify their chosen card after it is shuffled with 2 others or find a ball placed under 1 of 3 cups.
Here’s the answer to the test – it’s a scam – they switch out your card or remove the ball. You can’t win. If others are winning, then they’re in on the hustle.
Do your gambling in a regulated establishment, not with Tom, Bill, and Chuck in a shady corner on the Strip.