> There is no need for any verification beyond that or it's just government mandated surveillance.

There is no verification beyond that in these sorts of bills (CA, CO, IL). It's the parent's responsibility to watch their kids when they set up an account.

> Legitimate adult websites will not show the content.

This is a big problem (that won't necessarily be solved by this particular legislation, granted). There are already voluntary rating HTML tags websites can add to indicate parental control software should block them, but they're voluntary and non-standardized. Websites can choose not to comply with no real-world consequences. And I don't think platforms like Reddit or X, which are ostensibly all-ages social media but also have an abundance of adult content, are properly set up to serve tags like that on NSFW posts but not other ones.

It's a tricky problem to solve, and, imo, it's one the tech industry has demonstrated it doesn't have any desire to solve itself, hence legislation starting to get involved.

> Websites can send down a single header indicating adult content.

It sounds at first glance like a no-brainer that websites shouldn't have access to any information and the enforcement should be done at a local level (like the current voluntary HTML tags that locally installed parental control software can sometimes read). But some websites might want to display alternate content to minors-- e.g. a Wikipedia article with some images withheld, or Reddit sending a user back to an all-ages subreddit instead of just fully breaking or failing to load when the user stumbles upon something 18+. For anything like that, the website will need to know in some form that the user isn't able to see 18+ content.