While streaming your favorite show on Netflix via an Internet-connected smart TV, your data is being collected, according to a new study from Princeton University, which found that smart TVs are equipped with data-collecting trackers. Researchers built a bot that installed thousands of channels on both Roku and Amazon Fire TV devices and mimicked human behaviors like watching videos and browsing. When the bot ran into an ad, it tracked what data was collected. Researchers claim there’s little consumer awareness of this activity.

“If you use a device such as Roku and Amazon Fire TV, there are numerous companies that can build up a fairly comprehensive picture of what you’re watching,” Arvind Narayanan, associate professor of computer science at Princeton, wrote to The Verge. “There’s very little oversight or awareness of their practices, including where that data is being sold.” 

Narayanan and his co-author found that while some of the collected data (like device type, city, state, etc.) aren’t unique to one user, other collected data (like device serial number, Wi-Fi network, and more) could be used to identify one user. They went on to report that “some channels even sent unencrypted email addresses and video titles to the trackers. In total, the study found trackers on 69 percent of Roku channels and 89 percent of Amazon Fire channels,” reports The Verge. 

Data is part of the reason these smart TVs are getting more affordable. For example, a Roku sells for less than $200 because it’s partially subsidized by targeting advertising. Consumers technically agree to have their data sold when using these devices, though many aren’t aware. The same story goes for many other smart home devices, too, writes The Verge. 

Another study, this one out of Northeastern University, looked into 81 smart home devices and found that some monitor a user’s speaking or movement even when they’re not actually using the device. 

While devices like Roku and Amazon Fire allow users to turn off targeted advertising, “doing so only stops a user’s advertising ID from being tracked — not the other uniquely identifiable information,” explains The Verge. 

“Better privacy controls would certainly help, but they are ultimately band-aids,” said Narayanan. “The business model of targeted advertising on TVs is incompatible with privacy, and we need to confront that reality.”

The Princeton report is available online as a PDF.