For Bitcoin casinos, the system will automatically take a portion of the earnings for themselves during a specified time or when the user decides to divest.
For casinos that have POS coins, they can choose to also charge the user for their staked coins. Justdice does this.
I thought those wallets were locked and not allowed for POS. I didn't know JustDice does that.
I believe bankroll 'investments' are allowed by the casinos to spread their risks. Instead of them being hurt huge when someone wins big time they simply spread the losses to everyone else. The same way when someone losses big time too, it's a win-win.
