On the Connect app, there’s an option that users can enable to make user notes global. This applies a user tag to all accounts with the same username across instances. Any accounts that get a copy of the tag has an added * to denote that it wasn’t originally tagged; as a reminder since some people may simply have the same username on different instances.
I prefer to tag accounts over blocking because I think it’s beneficial to upvote pushback or correction replies, which you wouldn’t see by blocking. But some people have way too many alts and it’s rather tedious to tag each one. Granted, I also have many accounts, but that’s mainly for testing purposes.
Could this not be implemented with clever back-links to other “shared” accounts for users who care to keep this kind of thing connected? Kind of like how Mastodon works with web ownership verification, except for fediverse account linkage.
I would like to see an app or platform tackle something like this since I would like to see tagging functionality expanded. But unless an interested party develops something, I don’t think we’ll be seeing it anytime soon.