In the promotion by Atlantic Records, retailers in the southern United States will offer a free sample DVD to buyers of a CD by Nappy Roots, a hip-hop group. Once the packaging is opened, the disc will work for only eight hours before being made unreadable by a dye sandwiched between the DVD's layers that interacts with air, leaving it opaque.For promotional and rental materials, the time-limited discs look like a great idea, especially since cracking a disc would likely require chemistry rather than an easy download. Still, that doesn't mean that you wouldn't be able to rip a disc's contents before its time runs out.
Personally, I think this kind of thing would be perfect for DVD game and movie rental vending machines. DVDs are small enough to give the units good storage density, and you'd never have to worry about returns or late fees.