if it's ephemeral, it should not be cached. at all. if there is nobody to receive it, it goes to /dev/null use a regular, replaceable or parameterized replaceable if you want it to be cached. put an expiration on it, or update it frequently, as in replaceable. don't mix up the use cases by making the middle man do cache duty when there is a cache method existing already in the protocol. if your application is using ephemerals but you expect to need this, you should consider switching the events to replaceable or addressable events, and putting expiration timestamp tags on them. otherwise what happens when your realtime collab app gets confused when it drops the subscription and then gets 10 seconds of past events loaded into it.