If your bank is aware that a payment is going to an illegal gambling site, they are required to block it. However, the regulations don't require them to scrutin

If your bank is aware that a payment is going to an illegal gambling site, they are required to block it. However, the regulations don't require them to scrutinize checks since it's just not practical. Merchants who accept credit/debit cards must code the transaction for whatever their industry is, so those in the gambling industry are easy to block and banks are required to do so.