[radicality]

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.

[stavros]

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.