There needs to be a file storage location that behaves the way Caches did before iOS 5 I'm confused. If the goal is for documents to be available in the near f

There needs to be a file storage location that behaves the way Caches did before iOS 5 I'm confused. If the goal is for documents to be available in the near future in offline form, why not keep documents in /Documents until the user has read them (or some sane amount of time has passed), and then move them to /Caches or some temporary storage? I've never used Instapaper, so perhaps documents are only stored until read anyway?