it can work for nip60 since the relay set is (supposed to) be well set; but for the overall nostr that gets you into fork hell NIP-29 does this (kinda) with the `prev` tag because the relay you are publishing is well known, so you have a natural central repository of state -- it doesn't mandate rejecting events at all, but it gives you some type of contextual ordering of events in time.

reject the fucking event please! like a database, tell me when I do it wrong. no forking.

forking across relays is what you mean I suppose? in that case, I can resolve the fork with precision. I just need the relay to tell me I can or can't write this data. There is no other way.