Do they get adopted by other instances? Are they still accessible from other instances? Can you still post on them from another instance?
Edit: From my understanding every instance that deals with a community has a cached copy. Will that copy disappear after a certain time, because it can’t phone to home anymore?
I agree that would be nice. Hopefully it is something that will eventually get added as a possibility, but I don’t know enough about the background workings to say if it is being considered or not.