I'll let Gavin detail his use case, but I think the "root" is relative to each observer.
From my POV as a user, or the application running on my server, I think the "root" in this case would be the application account on each server. From there, we could branch out to see who WE trust, which is probably similar-but-not-quite-the-same as who someone else might trust.
Does that make sense?
Osma A 🇫🇮🇺🇦 (npub1h44…akl9) Gavin Chait; (npub1kmm…8pzf) Scott Jenson (npub1m8t…zu6r)