It seems desirable to let users manipulate RSVP statuses in the same way Google calendar does. For example, if a user RSVP's to an event, the user should be able to choose whether that RSVP applies to just that instance or to that and all subsequent instances in that series.

As a first step, it seems intuitive that a host's status should always start as "attending" and all future stubs should also be marked as "attending" until edited.