Big Brother is real - but it's not the government, it's the corporations. Facebook has patented a technology to embed high pitched audio (beyond the range of human hearing) into TV advertisements that will trigger your phone to record background noise. They claim this is to find out if you're actually watching the ads or if you mute the TV, leave the room, etc.
The reality is of course that they could record whatever they want.
Read more here: http://www.dailymail.co.uk/sciencetech/article-5882587/Facebook-wants-hide-secret-inaudible-messages-TV-ads-force-phone-record-audio.html
Personally I dropped Facebook over a year ago. I recommend you do the same.