I assume they still employ security guards to watch for people who walk in without a phone or amazon account, jump the turnstile, and start casually taking items off the shelf...

The packaging for every item must have an embedded RFID. An idea from about a decade back. One of the worries back then was that people could scan your garbage and learn a lot about you. People probably don't care about that nowadays.

It's not clear yet how many items are using RFID. They say they are using "computer vision, sensor fusion, and deep learning" akin to what is used in self-driving cars.

So there are some concerns if you pickup an item then put it back in the wrong place, will it detect it was still left in the store, or will it charge you? Putting it back in the right spot, refunds you, but it's not obvious otherwise.

We really need to know more from the Amazon employees that are using it.

It sounds a lot like Minority Report style stuff going on, and I think it is more a tech demo than a full concept they'll carry out in mass. The information on the path the customer takes, what they get and all that is probably worth a ton, and helps offset other costs with the system... though most of those costs are offset by having fewer employees... We are quickly reaching what CGP Grey noted in his video *relate=http://videosift.com/video/Humans-Need-Not-Apply where we need less and less people to do the lower end jobs... and those shelves look like they can be filled from the back, which is easier on robots.

Yeah I'm not sure if RFID alone would cut it. For instance, would the return signal from 15x RFIDs of the same item be distinguishable enough from 16x? I assume they would weigh items as well, just like the self checkouts. Waiting for the technical information.

How Amazon Will Monopolize All Of Retail - Nerdwriter has been added as a related post - related requested by eric3579 on that post.