They were not, actually.

IIRC, it went like this: the account creation screen prompted them for a birthdate. They entered a fictitious one and pretended to be over 13. (I saw my niece do this in front of me, and I just sighed a very heavy sigh. She was way more interested in Club Penguin.)

Then later, they let the cat out of the bag. They tell their friends "lol I'm only 10! Today's my birthday, so give me a hat!" or something. And so if they claimed they're 10 they got 3 years suspension.

I think there was never any verification done, and no verification was possible: think about it, under COPPA, a service in the USA cannot collect PII from children under 13, so what do you do when a kid gives you two contradicting datapoints? Err on the side of caution.

I gave Yahoo! a false birthdate when I signed up. I was 27, but I also just felt they weren't entitled to knowing it. However, I soon found that maintaining a fraudulent identity is tiresome and error-prone. And Yahoo! wouldn't let me simply change my birthdate as often as I wanted to.

I once had a conversation with a friend about cheating on IRS taxes. She said "can you lie to a piece of paper?" like fudging numbers wasn't like lying to an auditor's face. It was a rhetorical question, of course.