The comparison to an x-ray scanner is... well, lay off the nitro for a while. Really though, it's a completely different type of system. There's no way to identify individual items with x-rays. Even using an RFID tag on everything (the absolute simplest way to do it) runs into problems of cost. Each and every item would be marked up to cover the cost of implementing and tagging. Are you willing to pay $4-5 more each time you buy groceries just so you don't have to stand in line for five minutes? If you go weekly you're dropping $250 to skip out on 260 minutes of standing. I've got much better things to spend $60 an hour on, personally. This is ignoring the difficulties of such a system, which would require a large RFID scanner for each and every basket and figuring out how to eliminate crosstalk between devices which could end up with you paying for someone else's beets because they got too close to your machine. Which brings up another problem... anything sold by the pound would still have to be weighed and scanned at the point of sale and at that point you may as well just scan the other six things you have in the basket thereby negating the point of the entire system. It wouldn't prevent theft at all, btw. It would simply mean more people walk out of the store "empty handed" because they "didn't find anything they wanted."