Per physical copy, indeed. That's what would allow attribution of the sale to the store.
Even a QR code that provided a link that would allow an easy purchase for the ISBN would be great for publisher and the customer. It would, however, not be appealing to bookstores, since it just means the customer comes in, browses, and purchases it online, cutting out the bookstore that was playing a critical role in the process and cannibalizing its own sales.
You could create a bookstore-and-ISBN tuple that would also allow attribution without uniquely identifying each physical book. Probably improves privacy marginally (though it would provide a permanent indicator of which bookstore it was purchased from), but with the downside that it complicates things behind the scenes; what if one bookstore acquires another bookstore's inventory? And a bookstore ordering a new book would have to have its own individual print run.
You could handle that with geofencing, too. If somebody didn't want to participate in this scheme, they could easily not, after all. (Heck, you could even just have a separate code on the wall, to be scanned when prompted.)
Even a QR code that provided a link that would allow an easy purchase for the ISBN would be great for publisher and the customer. It would, however, not be appealing to bookstores, since it just means the customer comes in, browses, and purchases it online, cutting out the bookstore that was playing a critical role in the process and cannibalizing its own sales.
You could create a bookstore-and-ISBN tuple that would also allow attribution without uniquely identifying each physical book. Probably improves privacy marginally (though it would provide a permanent indicator of which bookstore it was purchased from), but with the downside that it complicates things behind the scenes; what if one bookstore acquires another bookstore's inventory? And a bookstore ordering a new book would have to have its own individual print run.