Sounds like you’d like some sort of event that refers to a previous event and asks relays to delete it. I think what Will is saying is that you can ask, but they don’t have to listen.

I think it’d be nice if there were a way to suppress one’s own previous messages, proving cryptographically that you were the person who generated the originals (or at least that you know the secret key of the person who did)

I think trying it would add significant overhead to relay costs though (think about how you’d implement it), and provides limited gains.

Is there a low cost way to implement it? Basically the problem is that relays that successfully hear your request need to store it for a long time, and always check to make sure they aren’t relaying the requested to be deleted note when they receive it from other relays who didn’t hear your request.

Some dude might stop running his relay after the regretted note and before the plz delete message, and then start it up again years later. If you or someone asks that relay for your note history, then his might not know the note you wanted suppressed was supposed to be.