@renchap @Claire What if instead of sending the raw actor id in a delete activity you send SHA256(actor id)? The deleted actor id would never be broadcast in the open, mitigating the privacy concern. Instance2 receiving a delete from Instance1 would SHA all its local Instance1 actor ids and if one of them matches, that's the one to delete.
@JasonPunyon @Claire I am not sure how this would solve the issue of needing to broadcast it to every known server? There is not really a privacy problem here, as you reference a no-longer-existing account