@LunaDragofelis @freakazoid @schratze
I konw why one would want that, but it would kinda brick it.

There's a reason why decentralized systems like #eMail, #XMPP & :activitypub: work on #DenyListing instead of #AllowListing, as this would inherently result in #centralization to an oligopol, something we see #iEmail like #Gmail, #YahooMail and #Microsoft #Outlook attempt.

Also do you really expect instance admins to vet every single self-hosted instance?
Cuz that won't work for a lot of people.