~
If they don't require any confirmation or if they don't have any deposit or withdrawal option, then there is a high chance scammer may scam them by double spending. I have never used these sites, so I have no idea about them.
None of those websites are active anymore, on-chain gambling which would involve paying a fee each time you place a bet and the casino paying a fee each time they would have to pay you, plus the millions of inputs would simply be impossible to manage in the current day, even with these low fees, you would still pay 5-10$ just in fees for some bets at the end of the day.
But my question is, if anyone misuses the double-spending option, then how can they prevent being scammed?
In those days, with no confirmation deposits
, no account on chain betting? You couldn't! That's why that type of casino has died!