I saw details of a very simple but brilliant scam recently.
Last year, someone bought 1.2 million personal email addresses. He then divided the list into two groups of about 600k each. On the first Saturday in May 2022 he sent an email to 600k saying that the Chicago Cubs would beat the St Louis Cardinals on that day. To the other 600k he sent an email saying that the St Louis Cardinals would beat the Chicago Cubs.
Following the result (the Cubs won) he divided the 600k from the first group into two lists of about 300k each. He binned the other 600k addresses. To the first 300k group he sent an email saying that the NY Yankees would beat the Oakland A's. To the second 300k group he sent an email saying the A's would beat the Yankees.
The A's won, so he took that 300k list and divided it into two lists of about 150k each and predicted the result of another ball game the following saturday.
And of the 150k in the correct result list, the following saturday he sent 75k another prediction, and 75k the opposite prediction.
And of the 75k he made two predictions to about 37.5k each. He took the 37.5k with the correct prediction and divided it again, into two list of about 18k each. When he'd arrived at about 18k people who remained on his list, he sent an email saying
"I can predict the future of every ball game being played from the biggest most sophisticated sporting algorithm ever developed. It's foolproof. I've sent you seven predictions and all were correct. I can send the algorithm to you for $5000, so you can make yourself millions of dollars beating the bookies. Baseball, football, basketball, tennis, horse racing, golf, it works for every sport. It's right every time. All you do is input the details, and it'll tell you the winner 100% of the time. If you are not a millionaire by Thanksgiving, I will give you your money back".
He made $3½ million by the first week of September.