This proposed amendment shows exactly why this entire concept is problematic. The definition of social media site is this:

> by regulations made my statutory instrument require all regulated user-to-user services to use highly-effective age assurance measures to prevent children under the age of 16 from becoming or being users.

Now imagine all of the user-to-user services you use on the internet: Hacker News, Discord, Signal, any messaging app, the comment section on your favorite news websites. Even Wikipedia is a user-to-user website.

The second point that people calling for heavy regulation neglect is that the only way to keep under-16s out of these websites is to enforce age verification on everyone who visits the website. So HN would require ID verification, and Discord, and your messaging apps. I always see ideas about creating age verification services that don’t disclose ID information, but a key part of age verification is confirming (as reasonably possible) that the person presenting the ID with the age on it is the same person who is trying to use the service. The same reason a 16 year old can’t walk into a liquor store with their mom’s ID is going to be applied to these age checks, requiring that the sites make an effort to associate an ID with the user. Otherwise, kids are smart and will borrow their parents or older friends’ IDs or even use online black market services if there are no negative consequences for sharing IDs that perform anonymous age checks. Associating IDs with user accounts is a key part of age check legislation.