You can do the same thing by putting the device in a faraday cage.
That would require everyone in the meeting to do the same. And Steve, Jared, Ivanka, anyone could be caught out discussing confidential matters to their loved ones in private.
42 posted on 03/06/2017 10:43:19 AM PST by Albion Wilde
("We will be one people, under one God, saluting one American flag." --Donald Trump)