I read a few years ago that most scams start in Las Vegas and then spread across the continental US. The reason these scams are developed in Las Vegas is that if you can scam a cynical Las Vegas resident who sees scams every day, then you can scam anyone.
Las Vegas has more than its share of scammers. One woman would stand on a street corner asking tourists for money. She looked obviously pregnant. Unfortunately she had been pregnant continuously for eight years (pregnancy prothesis). After nine months in one area, she would move to another area before the police were called.
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P.S. I am preparing some new subjects for the writing essays and fiction. Thanks for waiting.