What about saying in big bold letters 'requires constant electricity to function'?
That would be a ridiculous requirement, because people expect that TVs need electricity. But the producer can argue that people these days also expect TVs to need the internet, can't they?
I also use an AppleTV with my Samsung TV. I did give the tv WiFi credentials so that sometimes if needed it can reach the internet (eg firwmare download), but I set up firewall rules to block all traffic for the tv in steady state.
Trust me, you don't want your TV to download firmware. My Sony TV started freezing every so often after downloading some random update. Since then, it's gone off wifi and only the Chromecast is allowed to connect.
I can't decide if it's better to check for such things before purchase, or just return it as defective if I end up getting a model that does this.