Sure, and let's be clear about this. If someone's going to commit fraud, it's tough to guard against that, so let me address two points: one, how to do that, and two, the age of 16.
I think the age of 16 is consistent with laws across Canada. It's also consistent with the GDPR. To me that makes more sense. Just from a practical perspective, I don't think that children of the age of 13 can provide informed consent. To me, that's a non-starter. I question whether even at the age of 16 you can provide informed consent, but at some point you want to show respect for the youth as they grow up and mature, which is why I've also tied in the right of erasure to 18, which allows people to provide consent but then also recognizes that there may still be errors being made by children or by youth.
In terms of how this can be effected, when you sign up for a practice or sign up to an app or a website, you would be asking for a parental email account. One, you'd be confirming the age of the child, and you'd be asking for a secondary email account to verify the consent of a parent. It's not just that you go online but that an email is sent that is somehow verifiable and attributed to a parent, and they would have to also confirm.