What happened 

Launched at Amazon's cashier-less Go stores in the United States, Amazon One is a palm-scanning device that enables users to make purchases by placing their palms over a scanning device at the point of sale, with biometric data linked to a saved credit card. 

Beyond payments, the technology is also used for identification, age verification, and accessing venues and buildings.

Following the enactment of New York City’s Biometric Identifier Information Law in 2021, Amazon allegedly operated its "Just Walk Out" technology in New York locations without informing customers that they were being biometrically tracked, according to a 2023 lawsuit filed by the Surveillance Technology Oversight Project (STOP). 

Despite later adding signage, the suit argued the notices were poorly placed and misleadingly suggested that only those who opted into palm scanning were being monitored. It also claimed that the system's sensors and Amazon One palm scanners captured unique physical characteristics, such as hand shape and body size, to identify and track shoppers. 

Why it happened

The controversy was driven by the technical requirements of Amazon’s "Just Walk Out" system, which relies on "computer vision, deep learning algorithms, and sensor fusion" to distinguish between individuals in a crowded store. 

The controversy was exacerbated by transparency limitations: Amazon initially failed to provide the specific legal notices mandated by local privacy laws. 

Additionally, the company's decision to store biometric "signatures" in the AWS Cloud, rather than on a user's local device, raised red flags for security experts and lawmakers who viewed the centralised database as a potential high-value target for hackers.