That is very complicated. There's no time for regulators to identify who the parents are. The easiest way for them to take action is to sue the site for allowing minors. Of course, no gambling sites would permit a minor to gamble. Even if they don't require KYC at first, once you sign up with the site, you agree that you are not underage. However, in some cases, individuals may easily lie.
Therefore, as parents, we have a duty to always control what children access. In the case of those who misuse personal data, things like using data from the internet, stealing and currently a lot of personal data are also being sold. It's hard to appreciate, apart from being the parents' job, who really have to be able to monitor the child's movements when they are identified as accessing gambling.
Unfortunately, most parents don't do that these days, they give their children everything they want, mobiles, laptops, gaming consoles, internet devices, and everything else, and they don't even check what they do on them, that is the reason why many minors are seen gambling and even taking very rash decisions, some even reaching the stage where they commit suicide because they have spent money meant for other things on their gambling addiction.
All these things must be under the control of the parents, so that the children don't go out of hand and only do things that are not harmful for them and their parents, and if they do something like that, I would blame the parents more than the children themselves because they are not yet mature enough.