The privacy agreement in them covers it, just like Alexa.

Check yours, if you don't agree to the privacy agreement, things like cable and broadcast channel recognition don't work.

It also breaks Automatic Content Recognition, which enables the manufacturer to monitor what you're watching.

Granted that's not the same as listening, but it's close enough. And we know Google employees have been caught listening/watching people. There was another article just the other day of another company caught doing the same.

Just because something's illegal doesn't stop people from doing it.

As for catching it with monitoring... We know Microsoft has hard coded domain names into certain DLL's since XP, so you can't block the domains with a hosts file. There's some talk in the Pihole community about smart tv's being able to bypass your DNS with hard-coded IP destinations - they only need one to be able to then deliver their own DNS.

Some smart TV's will connect to others via wifi if they don't have connectivity, yet another way to bypass our efforts to block their connections.

That manufacturers are so blatantly adversarial makes it pretty clear they'll try to get away with anything they can. And anything I can think of, surely their dedicated teams of engineers thought of it long before me.

Edit: then there's apps like Netflix, Prime, Peacock, Hulu, YouTube, etc, that make encrypted connections to home. It would be trivial to permit those apps to deliver alternative name resolution for the entire OS on TV's since we don't control the OS.