I am well aware that the convenience of the various ways I do commerce and other things compromises my privacy. The kind of things you would have to do to make yourself completely opaque to these kind of things would be excruciating nowadays.

I wasn't too worried about my privacy in this case. I flagged this site because it's the first one I've seen like this that actually seems to do some real work of some kind to check you out, and I was wondering how they were doing it.

Most "over 17" sites I've seen (looking at things like certain anime art and sculptures for example) involve simply checking a box that says you're over 17. I have no idea what laws that actually satisfies, but it seems to work.