that is the dilemma of some parents who have underage kids, as they can't look after them 24/7, and the access today is quite easy as 1-2-3, they can just rely on the teachings they give to their kids at home and hope that they won't go off course.
and let's admit that most casinos care for how much they can take in from their players, usually they will only flag down the account if they see big winnings and want to stall paying their winnings.
That's one bad scenario you have a kid winning a huge amount of money, he used his real name and not thinking that one day he can win a big amount of money, and yet being a kid can not have that amount, these kids will then learn to manipulate KYC, so letting kids play in casinos will not only make him addicted to gambling at an early age but there's a possibility that he will be exposed to corruption, kids nowadays are imaginative.