They would never know. They don't let you use it if you're under 13; there are probably tens of millions of children using it.

Until someone doesn't like one of your posts and reports your account as a fake. Then it gets locked and they make you scan your drivers license and send it in. I've seen this happen to people who do things as innocuous as put a nickname between their first and last name.

Sure, but then you create another fake account. In any event, my original suggestion was for people who simply wanted to silently join groups to read info, and/or avoid annoying login requests.

Which is not always a bad thing. It allows comments on community websites without getting most spam, trolls, sexist abuse and so on. Which is a large part of why things like community websites have moved there.