But from the casino's point of view, the "long run" is much shorter. They have many players playing many games, and that cuts down the variance. And a casino doesn't max out its short run by telling people to stop playing. They would take most people's lifetime's worth of action is less than a month. I can certainly by that there is a risk aspect in the highest players, where a few big wins could move the overall financial performance line. But that would not explain why the lines are relative to average bet. One 100k bet isn't killing the casino, even in a game with odds. Plus you can give the player the line but they still need approval to raise the table limit to bet it all at once.