Recently I've had to deal with this same problem - get a new TV for living room. Personally, I do not watch TV at all, but kids want to see cartoons when having their breakfast. I spent a week reading forums and came to conclusion that best solution would be to buy a "dumb TV" and connect it to a PC I trust, but it appears there are no dump TVs in my rage of 55" and larger. So, I bought "Google TV" based TCL.

When I brought it home, I never connected it to Ethernet or WiFi. Instead, I connected it to my laptop over USB, then using adb I uninstalled almost every application from it. It took me quite some time to figure out what app is possible to remove and what should be kept to let TV functionality to work. I even had to factor-default it a couple of times because some random apps I removed were crucial for Android to work. :) I think it took me 5-6 hours to clean it. Now it has only basic TV functionality like any dump TV does, I can watch air and cable TV channels, watch movies and play music from USB storage. If there's a need to watch something online, I connect it over HDMI to my small mini-PC that runs FreeBSD. I think I'm satisfied with the result. :-)

PS: Yesterday I opened the case and disconnected WiFi antenna. Just in case.