Edge... That is the basis for Gamefly's "Fast Return" as well:
In partnership with the U.S. Postal Service, GameFly is launching the FastReturn™ service designed to improve delivery turnaround time.
What is FastReturn™/How does it work: When you return a game in the mail, the U.S. Postal Service may scan the return and send a confirmation to us. As soon as we receive the confirmation from the U.S. Postal Service that a game has been returned, FastReturn™ will start the processing of your next game and send a message to Your GameQ.