Note: This post has been updated since first published to include comment from Amazon.

As Amazon scouts for its second headquarters and continues to expand its workforce beyond a half a million people, the country's second-largest employer must continue to find ways to become more efficient. And it may have a new high-tech way to do so: bracelets that track every move its warehouse workers make.

The tech giant was awarded two patents for a wristband system that tracks workers' hand movements in real-time, GeekWire first reported Tuesday. The technology in the wristbands "could emit ultrasonic sound pulses or radio transmissions" to let a receiving system know where the workers' hands are in relation to the inventory bins. The idea is that such a system could help employees find the correct bin faster and with fewer errors.

Amazon has not confirmed whether the patent applications, which were filed in 2016, will become a reality. A company spokeswoman emailed a statement to Inc.:

The speculation about this patent is misguided. Every day at companies around the world, employees use handheld scanners to check inventory and fulfill orders. This idea, if implemented in the future, would improve the process for our fulfillment associates. By moving equipment to associates' wrists, we could free up their hands from scanners and their eyes from computer screens...Like most companies, we have performance expectations for every Amazon employee and we measure actual performance against those expectations, and they are not designed to track employees or limit their abilities to take breaks.

Amazon isn't the first company to explore the idea of employee location trackers for purposes of productivity. Pediatric nurses at the University of California-San Francisco Medical Center are required to wear electronic locators that monitor every step. Humanyze, a Boston-based startup, has implemented biometrics in employee ID badges that track everything from movements to lengths of conversations to even tone of voices. Tracking devices are already used among security guards, casinos, restaurant workers, and miners. Research has found that tracking devices can increase productivity, at least, in the short term. The technology also is becoming increasingly advanced and can be used to monitor HR violations such as sexual harassment and inappropriate behavior.

But tracking every step employees take raises obvious privacy concerns. Just because a company can increase productivity by surveilling employees on the job, should it? The laws around tracking devices are not that clear. There's no federal privacy law to keep businesses from tracking their employees with GPS. In 2015, a woman sued her former employer Intermex Wire Transfers, claiming that she had been fired for disabling a GPS app on her company-issued phone after she found out that her location was being tracked 24/7.

Even if Amazon doesn't implement the technology, it already relies on automation and tracking with one crucial part of its workforce--the company has more than 100,000 robots rolling around its warehouses around the world, according to The New York Times. As Martin Ford, futurist and author of "Rise of the Robots" pointed out to the Times, without these bots, Amazon would not be able to deliver cheap costs or two-day shopping for its customers.