I had a guy contact me about buying a Minecraft account a few months ago. It was an account held by a highschool friend of mine with a three-letter username that is a word, making it incredibly unique.

He identified the now-unmonitored email address associated with it, found that email in leaked logs from a forum, then searched for other hits from the same IP in the same time range. That forum access was from my house, so he found my email associated with it elsewhere.

He successfully identified another friend of ours at the same time. All from a single dynamic IP fifteen years ago.

Wikipedia blocks edits from pretty much all public VPNs and is very harsh with IP bans in general. They do allow edits without accounts though, so they show the IP so that an accountless user can be identified when making multiple edits or posting on the talk page. Hashing it would probably make more sense.