But this is a more flexible system than it sounds. It allows any device to start tagging devices and their users regardless of network, carrier and operating system. It's not detectable as malware, and a VPN won't block it. It's frankly brilliant. Alterations in frequency can be used to tag unique nodes. With sound strength as a proxy variable for distance. if one device in the area has geolocation enabled, the whole cluster is identified. #survellance #SurveillanceAds #capitalism
https://arstechnica.com/information-technology/2017/05/theres-a-spike-in-android-apps-that-covertly-listen-for-inaudible-sounds-in-ads/