Of course, the only thing more troubling than robots replacing human workers is the idea of robots tracking human workers' hands, but i) there are profit margins to be optimized and ii) this is the same concept of being under house arrest with an ankle bracelet, it just happens that Amazon wants to put the device on the worker's wrist.

On January 30, 2018, the U.S. Patent and Trademark Office (USPTO) issued Amazon two patents for wristbands that would use ultrasonic tracking technology to identify the precise location of a workers' hand as they perform tasks within the Amazon warehouse.

The United States Patent 9,881,276: "Ultrasonic bracelet and receiver for detecting position in 2D plane."

The United States Patent 9,881,277:  "Wristband haptic feedback system."