Let me be more methodical here.
There are 4 types of posts:
1. to outbox/inbox relays
2. to outbox/inbox relays and also to the currently active relay
3. only to the currently active relay
4. only to the currently active relay with "-"
(Now thinking about I think we can go up to 16 combinations or perhaps 32, but these give us an idea already.)
I think 2 is never desirable. If it is it's a niche case that can be achieved manually with the "republish" functionality.
I can't think of any use cases for 3.