Should those events have an expiration/ttL so clients can cache them?
Discussion
We can add, for sure. Do we need to do it by `A` record or can we do it for the whole thing with `expiration`.
Either way, Clients should cache it.
If the tags are individual records then each should have their own TTL
The expiration tag is for relays to know when to delete the event which is NOT what we want here. Otherwise a new event needs to be published.
The TTL is for clients to know when they should invalidate their cached version