It's funny you mention that. There's a dude I work with that hasn't met a CT he doesn't like...including ones he makes up clearly out of thin air...
He believes that all Smoke and CO Detectors have microphones built in that record every sound in your dwelling (the blinking red light gives it away). Then a Gov't Black Truck can drive up and wirelessly download the info at their leisure.
Of course, I asked why the red light means it's a recorder...seeing that they don't
need a red light to record things. He says it's the only way they can track the infrared signal from the device....LOL
I'll have to ask him if he has "inside" knowledge of the "red stuff in da tub".