Who shoplifts DVDs anyway?
Whoever thought of this ingenious idea is missing one subtle, but nonetheless rather important, little pointette: nobody actually shoplifts DVDs!
In record stores, there are the usual passive RF devices on each of the cases. In supermarkets, which carry a smaller range, the cases are empty and an assistant, bringing the disc, is summoned when the barcode is scanned.
The only thing I can see this being any use in defeating is when people walk into a store with a laptop PC, open a DVD case, rip off the movie and leave with only a copy on their HDD ..... but that's just so obvious, I can't believe anybody actually does it. And it won't prevent store staff from secretly making copies in the stockroom, seeing as they already have access to the machinery for making the discs watchable.
If the activation device embedded in the disc fails (and it sounds like an overly-complicated scheme; we all know that complication is the horse on which failure rides into town), then the purchaser is denied the use of the disc they have bought and paid for. This is going to increase the cost to retailers (who, under the Sale of Goods Act 1979, will be held responsible for replacing defective DVDs and will then have to try to recover the cost from the distributor). If the machine at the till which triggers the on-disc activation device fails, then the shop will be unable to sell any DVDs from that till. The result will be chaos. The combination of these two failure modes is likely to end up costing more than the shoplifting it was designed to prevent -- particularly since it won't even stop the little scrotes from nicking the discs, if all they want is just to annoy people.
Why can't the DVD industry learn from the printed media industry? Almost every bookshop and newsagent has a photocopier; yet you never see anyone using it to rip off newspapers, magazines or the latest "Harry Potter" novel. I hope I don't need to point out -why- this is the case.