All this said I'm more concerned about Automatic Content Recognition (ACR) on smartTV you buy in the store and never even realize it's phoning home with everything you watch...
Unless encryption is advertised as a feature, it’s a safe assumption that vendors that host your data will have access to it, the cloud being someone else’s computer and all that.
I wouldn't use Apple TV, Shield or other proprietary black boxes if you want a private setup. Linux on a mini-PC with Plasma Bigscreen, your own over-the-air antenna for local TV, VacuumTube for YT, and the high seas for other content.
I'm certain there are a non-zero number of TVs that either attempt to auto-join popular wifi hotspots (xfinity/tmobile/starbucks/etc.) and/or have cellular connections for telemetry.
Thinking more on this I think a business opportunity in the future will be companies that design hardware stacks that can go in random appliances that can gather usage information in the name of telemetry.
I give it +/- 5 years before an OTS coffee maker at walmart phones home.
You’re more concerned about privacy when it comes to TV viewing than medical data? What a strange hijacking of a serious thread…