A few years ago Google wanted to record a few seconds of sound from the homes of people using the microphones/speakers on their computers.
I'm quite sure it was the computer speaker since not every computer has a microphone but most if not all have speakers and a speaker is really a just a reverse microphone.
People freaked out over that so I'd say recording live streams of video would be worse especially considering some things people may be looking at each day would be very private.