I have just logged in on my own Lemmy instance, and I see a list of banned users in the administrative area, from other instances. I have not banned anyone myself.
How does it work? If you’re banned from an instance, you’re banned from the whole federation?
That would imply that any instance admin, even those that created theirs for themself only, can just ban users on other instance. That would be a major attack vector and it kind of defeats the purpose of the autonomy each instance is supposed to have…
I assume it only gets shared when the admin of the instance where the user is registered bans them, but again, that’s only a guess.
Go to the modlog of your instance and you can see they were banned of the mod of the original instance.
And that would mean I can set up my own instance, ban e.g. you, and you’d get banned on other instances as well. That doesn’t sound like a well thought out design choice.