when an event is private, sure, there's a good reason for that, privacy, but anyhow most clients try to find posts by ID on all of the relays in the list if they don't have relay hints... and then you get 10 copies of the events
unless the client is given an entity to find the post this is how it works, but it would be helpful if it were simple to propagate the results back to your write relays so that they are there for next time or for anyone else using the same relay looking for the same things