Definitely the `Chain of Trust` concept can be applied to anything. For example Social Media Protocol developers have thought a lot about using CoTrust, to be able to block undesirable people (moderation), by following a 'whitelist' only of users you trust or ones they trust, down a dependency tree of trust. Interestingly you could decentralize this onto some Relay system like Nostr and use Crypto signing, where each "trust" is Crypto certified to be correct, rather than needing to truse a central server/authority.