You may already be aware of this issue, but it is new to me. I first learned about it today form: http://www.zdnet.com/article/hundre...17cfd61&bhid=21920984823979904861134656766145. One of the referenced papers is from http://ubeacsec.org/, and they have a Chrome Browser extension to filter out ultrasonic sound (see http://ubeacsec.org/#Downloads) plus a patch to Android to change microphone permission request to halt ultrasonic sound use. Both released under the Apache 2.0 license. Is this something that could be implemented for Android and Windows, which are the main two platforms I use the most?