Hiding devices in lights and ID badges, your boss can legally track you everywhere but the bathroom.

About a year ago, journalists at a British newspaper found little black boxes installed under their desks. The devices, which had “OccupEye” emblazoned on them, detected if employees were at their workstations. Not shockingly, writers and editors were suspicious, worried that bosses were monitoring their moves, even their bathroom breaks.

The National Union of Journalists complained to management about Big Brother-style surveillance. The company insisted the boxes were intended to reduce energy costs, ensuring that empty cubicles weren’t overheated or over-air-conditioned, but the damage was done, and the devices were removed.

Most people, when they walk into buildings, don’t even notice them,” says Joe Costello, chief executive officer of Enlighted, whose sensors, he says, are collecting data at more than 350 companies, including 15% of the Fortune 500. They’re hidden in lights, ID badges, and elsewhere, tracking things such as conference room usage, employee whereabouts, and “latency” - how long someone goes without speaking to another co-worker.

Legally speaking, U.S. businesses are ... within their rights to go full-on Eye of Sauron. “Employers can do any kind of monitoring they want in the workplace that doesn’t involve the bathroom,” says Lewis Maltby, president of the National Workrights Institute. And as long as the data is anonymized, as Enlighted’s is, some people don’t mind tracking if it makes work life easier.