Is this different than any other embedded webview? Doesn't nearly every app somewhere have an embedded webview somewhere for things like "view privacy policy", where it is often much easier to display html than sending the whole privacy policy to your app developer?
Do normal embedded webviews also bypass parental controls? If so, that seems like a massive issue.
I can't find any information anywhere that either confirms or denies the possibility to bypass Google's restrictions with web views. I assume it's possible, because it's possible on most platforms, but I suppose it depends on the implementation.
I've seen parental controls that employ an (on-device) MitM proxy and DNS filtering to ensure safety, and those apps will prevent almost any app from displaying unwanted content.