A shopper scans a smartphone app associated with his Amazon account and credit card information to enter the Amazon Go store in Seattle, Washington, U.S., January 18, 2018. Photo taken January 18, 2018. REUTERS/Jeffrey Dastin

Shoppers enter the Amazon Go store located in Amazon's "Day 1" office building in Seattle, Washington, U.S., January 18, 2018. Photo taken January 18, 2018. REUTERS/Jeffrey Dastin

A customer browses meal-kit options at Amazon's new "grab-and-go" store in Seattle, Washington, U.S., January 18, 2018. Photo taken January 18, 2018. Image for illustrative purposes. REUTERS/Jeffrey Dastin

Signage is seen inside Amazon’s first cash register-free grocery store, in Seattle, Washington, U.S., January 18, 2018. Photo taken January 18, 2018. REUTERS/Jeffrey Dastin

A customer walks out of the Amazon Go store, without needing to pay at a cash register due to cameras, sensors and other technology that track goods that shoppers remove from shelves and bill them automatically after they leave, in Seattle, Washington, U.S., January 18, 2018. Photo taken January 18, 2018. REUTERS/Jeffrey Dastin

Amazon-branded chocolate bars are seen in the company's convenience store Amazon Go without checkout lines, in Seattle, Washington, U.S., January 18, 2018. Photo taken January 18, 2018. REUTERS/Jeffrey Dastin

A shopper is seen using his phone in the line-free, Amazon Go store in Seattle, Washington, U.S., January 18, 2018. Photo taken January 18, 2018. REUTERS/Jeffrey Dastin

An Amazon employee manages inventory in the company's line-free Seattle store, in Seattle, Washington, U.S., January 18, 2018. Image for illustrative purposes. Photo taken January 18, 2018. REUTERS/Jeffrey Dastin

An Amazon employee manages inventory in the company's line-free Seattle store days before the store's public debut, in Seattle, Washington, U.S., January 18, 2018. Photo taken January 18, 2018. REUTERS/Jeffrey Dastin

Customers browse packaged wraps, sandwiches and salads at Amazon's new "grab-and-go" store in Seattle, Washington, U.S., January 18, 2018. Photo taken January 18, 2018. REUTERS/Jeffrey Dastin