So you bought a genuine item to get its tag, don't you now have a problem of what to do with your genuine item? Sell it with fake ID?
* The attacker might have physical access to the genuine item, but not have ownership of it. A counterfeit seller might peel of stickers in a legitimate store, and use them in the fake store. Walking out with a bunch of stickers in a Farraday cage is a lot easier than walking off with the actual merchandise. The original retailer is then stuck with an unauthenticatable genuine item.
* The attacker might transplant a sticker from a defective genuine item (e.g. in a repair shop) to a counterfeit item. The genuine item was already worthless at this point.
* The attacker might transplant a sticker from an authorized object (e.g. locked suitcase that has passed inspection) to an unauthorized object (e.g. locked suitcase with contraband). The original object can then be discarded.
This tech would prevent each of these attacks (should it prove pracical)