Yeah, the thing is we don't require them on the server-side. If the client decides *not* to use them, they are assuming that whatever state the server-side replica is at will be fine. An example use-case -- only one thread/client does deletions from sets (being handed them from a queue or something), while all others only add. In this case the context would not be necessary, as long as you don't suddenly have all fallbacks for the preflist.