You pretty much nailed the concept of cash on hand in the vault vs. cash in the bank. At least in Vegas, they really do adjust whats in the vault in the building based on the action on the floor, they theoretically have to be able to cover all wagers on the floor. So, for example, on a weekend where sports betting would be high (Super Bowl, a UFC fight, etc.) they would increase whats in the vault to cover those multi-thousand dollar or multi-million dollar bets. Conversely, there are no professional sporting events the day before or the day after the MLB All-Star Game, so very little sports action, and they wouldn’t need to carry as much in the vault.