He might have to wait in line though. Which really touches on what the Amazon service is good for. They should be focusing on putting their technology in gas stations and convenience stores, not supermarkets. It would be great to just go in and grab a few things and walk out. Where as in a Grocery store, the french version is much better.
There is often fast lines for clients with less than x products. They should generalize this system for carts and keep the lines for on-the-go clients.