The age limit placed on people below 18 year to keep them away frim gambling have not been most effective as we have hard records of under age gambling in many place and this is a pointer that casino has indeed misolaced their primary responsibility which is to prevent that from happening and that is why there is need for KYC.
Age limit is not a determinant to gambling responsibly because if we are going to address this as a whole from the scratch we could discover more that the aged ones often be the ones that abuses gambling by being addicted or found misbehaving while gambling which shouldn't be, but i can't blame some of them because they have gamble away what could have been of a benefit to them long time ago, what they now do is to forcefully gamble through inner frustrations.