Check Outs of the Past

LA Times Article:  On the state of the supermarket checkout and coming expected migration to smartphones.   With a pointer to technologies of times past that we experimented with in much detail:    " ... Ten years ago, shoppers envisioned a day when radio-frequency identification tags would enable them to whisk shopping carts through a checkout without unloading them — or bypass the checkout lane and ring up groceries as they walked through the store. But RFID never got cheap enough for razor-thin grocery margins. And we're still stacking groceries on conveyor belts, a 19th-century invention.... "