I don't think there's any effective way of determining it's spam. Maybe WoT?
if itβs using a NIP-05 that belongs to another pleb thatβs the owner, should be easy. One nsec/npub owns it any other that adds it to their profile as a username or whatever would be labeled spam
Oh yeah, trying to use a nip05 someone else has registered won't validate, at least it shouldn't (the client should verify it against the users' pubkey used in the app). Adding a spam label would add another level of awareness π
But this won't stop them from registering a similar nip05, which is what I was referring to when I mentioned address as a service websites.