Dennis Nikrasch doesn’t do things by half measures, and is known to have carried out the largest slot machine scam in Las Vegas casino history. He profited from his scam to the tune of $16,000,000+ and the scheme itself falls more under opportunism than ingenious.
Nikrasch and his motley crew would distract slot machine mechanics with the aim of making an imprint of the key to enable them to unlock the machine. They would then later return and set the reels to the jackpot winning combination. In 1986 this technique worked for them to the tune of $10 million.
Amazingly many casinos still hadn’t got wise to the scam and they repeated it in 1998 winning another $6 million. They were eventually caught, but how much they really made over the years is to this day a mystery. Some have suggested it could be as much as $4,000,000 a year.