In talking with nebulae and Lilibette, we hit upon a novel use of the multi-instance capability of scenes. Often in SL people would like to go to a sim with nobody else there except perhaps their partner or a few friends. This is like going to Disney World and not having to wait in any lines to go on the rides.
I realize this may mean spinning up additional scene servers, but I suspect this would not significantly increase the overall demand. Further, we have all been complaining about the downsides of scene instance splitting, so why not put it to a use that makes people happy? It would definitely be something that SL can't offer.
How would the interface work? Two UI features should do it. First, modify the "Visit" button to have an optional little drop-down menu with options like "Visit with everybody else" and "Visit by myself". Second, offer a proper teleport-someone feature. Someone who follows a teleport offer would end up in the same instance. In a case where there's no more room in an instance, they would be told of this and be offered the option to visit a different instance instead.