I think they will be limited to their responsibilities. If the casino brings any allegations of money laundering against a client, their business may suffer in a way that they would never want. If they are asked to investigate these illegal activities, they will not do that because they have no need to investigate the gambler's finances. What casinos can do is ask each gambler for their KYC. If they get any error then they can take necessary action. Money laundering is an illegal activity, every casino should discourage such activity.