Retaining the reference to NSManagedObjectID is actually safer than passing around a potentially faulted NSManagedObject.  We really shouldn't be passing ANY NSManagedObjects to other classes because it implies that the accessing of properties must happen on the same context as where it came from.

If the Blog is deleted that is passed over to BlogSelectorViewController it should return nil when fetched by ID and then continue on it's merry way.