I became fully aware of this when a few months ago, my Xiaomi smart TV turned on by itself and displayed an AD to subscribe to Netflix (I did have the Netflix app installed because I had an account a while ago, but I had already unsubscribed, I simply forgot to uninstall the app).

Needless to say, from that moment onwards, no wifi and no ethernet for the TV. I got an Xbox with Kodi connected to it. I am not saying the Xbox is immune to data harvesting (probably they collect a fair bit), but feels less intrusive and obnoxious than the whole package of the smart TV.