Quite interesting topic, perhaps those who have been banned from casinos it has been because managed to make a deal with supernatural beings, so they always pocket a good money out the casino and get away with it. 
Haha, that's one wild theory! Lol. I guess if someone always walks out a winner, people start thinking there's more than just luck or skill at play, maybe a ghost giving them signals at the roulette table? Lol But realistically, casinos (physical casinos) are quick to notice patterns that hurt their bottom line. Whether it's card counting or just a lucky streak, they'll find a way to shut it down, no supernatural contract needed.even though it's just their imagination that makes their subconscious believe that the help of an invisible creature will give victory.
When it comes to the supernatural, I often see the movie "GOD OF GAMBLERS" because the character has the power to control and see how many dice come out and more magical things are done,
maybe people who still believe in the mystical thing in gambling are still inspired by such movies.
