2 ideas that could reduce spam/scam activity on Nostr:
1) set a satoshi paywall for non followers to message you
2) set a minimum follower-to-following ratio rule before someone can follow you
βIf the federal government had access to every email you've ever written and every phone call you've ever made, it's almost certain that they could find something you've done which violates a provision in the 27,000 pages of federal statues or 10,000 administrative regulations. You probably do have something to hide, you just don't know it yet.β
-- Moxie Marlinspike