Whenever we identify a gambling transaction, we'll automatically block it. If a transaction isn't identified as a gambling transaction, we won't be able to block it. Lottery tickets bought at supermarkets, or cash withdrawals from casino ATMs won't be blocked, for example.
Most large issuers don't allow online gambling purchases\n\n For example, Chase no longer explicitly lists online gambling as an illegal activity, but that doesn't mean the bank is routinely approving those purchases, either.