I get the privacy concern in regards to advertising ones age, but I wonder if this is akin to a underage walking into a liquor store, interacting with stranger adults, etc. There are obvious appropriate and inappropriate behaviors to minors.

Let's confine only of consumer OS and is provisioned with an underage bracket (you set it to what you want, And Not a Require verify). All sites/app the OS interacts must honor certain child protection laws (privacy, selling, gathering etc)?

What is the main discussion surrounding placing (by choice) some 'optional' age bracket to enter during the OS setup/provisioning? The OS as provider only declares an age and it seems the sites/apps it interacts with to be the ones in the hook, not the OS.