More simply: If ID checks are fully anonymous (as many here propose when the topic comes up) then every kid will just have their friends’ older sibling ID verify their account one afternoon. Or they’ll steal their parents’ ID when they’re not looking.

Digital ID with binary assertion in the device is an API call that Apple's app store curation can ensure is called on app launch or switch. Just checking on launch or focus resolves that problem. It's no longer the account being verified per se, it's the account and the use.