I don't know if mainstream apps are doing that, but I don't see why someone couldn't create a "trojan horse" app that requires the microphone, and starts monito

I don't know if mainstream apps are doing that, but I don't see why someone couldn't create a "trojan horse" app that requires the microphone, and starts monitoring and sending back recordings if it detects a conversation, it probably would be eventually spotted though if it gets any populartity. Or, perhaps microphones in public that try to tie overheard conversations with beacon or location data to find out who it heard.