Now called "drip casting," the technique is what engineers call "store and forward." The idea is that when a consumer wants to watch a movie, the carrier could offer incentives to order ahead of time, instead of "now," allowing the carrier to stage delivery of the bits over time, at times when the network isn't congested and can more easily handle the load.
The value exchange could be as simple as "use drip casting and the data won't count against your data cap." Drip-casting
Video content distributors also use the concept, though not for reasons of bandwidth efficiency. Tivo, or any other digital video recorder, essentially "catches" data when it actually is transmitted and then stores it for later viewing. It's a variation of the basic technique, which is that transmission of data and consumption of that data occur in non-real time.
The other angle here is that the plan is a bit of a shift in the direction of value-based charging, where the "price" or "rate" for some use of the network varies based on the value of the sessions, or the timing of the sessions.
In this case, consumers receive the value of a big download that isn't charged against their data plan, while the service provider receives the value of alleviating strain on the network.