Coin-matching is played all over the world and can be played legitimately. Anyway, some people use it for the unfair benefit of themselves by scamming others.
The scheme is normally run by two controllers. The first controller, along with the victim, enters the game. Then the second controller enters soon afterward and continues to lose the game.
After pretending to call the police, they persuade the victim to give them hush money, and the two controllers then broke up.