Board Thread:General Discussion/@comment-45571174-20200917215136/@comment-9605025-20200921224512

Believe it or not, some users are stupid enough to brag about how they circumvented Fandom's age restrictions by either editing anonymously or by lying about their age at registration. That is one way Fandom can tell an anon is underaged.

I don't know the details of how they deal with underaged anons. If you want to know, ask staff. However, I would assume it involves a temporary block at a minimum.