No, it sounds to me like a sophisticated version of caching. Content is downloaded to a buffer which is deleted after use. That pretty much leaves cable as the only usable connection.
Well, it could be "cached" locally, remotely, wherever, but the "rights management" is definitely going to be out of the users hands. Don't expect to be able to see anything unless whatever "membership" to to iDisk is up to date - even if you had previously "paid" for it. The future trend is "everything is a rental".