This seems like a credulous argument based on no facts you have provided.

If you explained how the box was hooked up, it would be easier to judge whether there was a chance you were correct.

As it is, your description isn’t even clear whether or not the box contains a microphone.

nielsen's ACR method is embedded into millions of devices and vendors. No need for a microphone, it's processing the audio signal being sent out. A microphone would be a wasted conversion..

(your car infotainment also likely has nielsen tech in it most likely, as they bought arbitron and gracenote)

Nielsen is global Company that is used for pricing ads on TV stations around the world. Their way of doing it from what I know personally is that they sign up people to put this ACR boxes voluntarily and then based on extrapolation of data - they can tell you pretty close what was the viewership across demographics. Similar to how election polls are done - you just need a good sample.

It's been done for at least good 15 years.

LMGTFY was made for people like you.

You know you can look it up if you are skeptical, right?