be violating the FTC Act if they state or imply that their apps are not tracking television viewing habits when they in fact are. Applications Studies have shown that 234 Android applications are eavesdropping on these ultrasonic channels without the user's awareness. Applications such as SilverPush, Shopkick, and Lisnr are part of an "ultrasonic side-channel" in which the app, often unbeknownst to the user, intercepts ultrasonic signals emitted from the user's environment, such as from a TV, to track which advertisements the user has heard and how long the person listened to them. SilverPush––the leading company using this technology––patented software enabling them to track TV ads based on audio stream above Shopkick, another popular application, gives discounts to users who shop at stores which emit these ultrasonic beacons, allowing them to create a profile of the user Lisnr uses a user's location data in tandem with ultrasonic beacons to give users coupons related to their activities Another study suggested that Apple, Google, and Bluetooth Special Interest groups need to do more to prevent cross-device tracking. Privacy and surveillance concerns Ultrasonic tracking Cross-device tracking has privacy implications and allows for more detailed tracking of users than traditional tracking methods. Data can be collected from multiple devices used by a single user and correlated to form a more accurate picture of the person being tracked. Moreover, malicious actors may use variants of the technology to de-anonymize anonymity network users. Ultrasonic tracking technologies can pose massive threats to a user's privacy. There are four primary privacy concerns associated with this new form of tracking: The first is media tracking: audio from the user's television may be detected by the microphone in the user's mobile device, allowing malicious actors to gain access to what the user is watching––particularly if it is salacious. Advertisers can similarly gain insight into what a user typically watches. In both scenarios, a user's real-world behavior is linked to their online identity and used for tracking. Another form of tracking permitted by ultrasonic tracking is cross-device tracking, which enables a user's profile to be connected across multiple devices based on proximity. This form of tracking, in linking different devices, can help advertisers show more targeted ads or open individuals to attacks by malicious actors. Location tracking is yet another privacy concern. Indeed, ultrasonic signals can convey location information via a location identifier, often placed in stores or businesses. Lastly, this