So the collection page object can also be… paginated?
It's a B-tree?
Also because OrderedCollection is defined as a type of Collection, you could presumably have your Collection object return OrderedCollectionPages, or even a mix of Collection and OrderedCollectionPages.
Which means you're back to checking for orderedItems after all, even when you think you have a "collection" object, as soon as you deserialize the page.
Back up to the Collection itself.
8/