Sure, you can imagine it, but you should be able to imagine better solutions too. Far easier to ask for a government ID, or better yet, have a third party, which is trusted, use a cross-check, so that the raw data is never shared, just a binary, yes/no to the age check.

If we only imagine the bad outcomes, we'll miss on many good ones. And part of those misses will be worse bad outcomes. For example, if you object to the creation of a third party that could validate your age, what you get is a direct ask for your ID, which is the current reality and far worse.