An strfry plugin most people should be applying: https://gitlab.com/soapbox-pub/strfry-policies/-/blob/develop/hellthread-policy.ts
Discussion
What about the whole nostr design principle of "relays should be dumb"?
This probably best done on the client and controlled by the user. 🐶🐾🫡
Also implemented here: https://code.pobblelabs.org/fossil/nostr_relay/info/a78d8cf73becb166