It remains all superstition to me, one of the many superstitions surrounding gambling. If a madman can give correct predictions for a game, why has no shaman or prophet been able to give correct score predictions for several games?
Most times the people who tell this kind of story always claim to have heard it from another person; it is rarely a firsthand experience.
I think games from insane or mad person is not usual, it is rear. they act upon a driven force and or influence which makes them to give those games. I hope you understand better because you are African, you should know better. But be thou as It may, no game is a sure game until it is proven to be sure after results. Even not all game given by insane, mythical people or prophet usually play, they have higher chances of loss. It all bounce back to luck. Although people have different believes and it works for them according to how they believe.
In other words gambling is spiritual inclined and need a powerful spell to get predictions which mostly can take a human life that is why threw mythical people are afraid to use it to win.