Definitely not users (useds?) of proprietary software. Use monitors for privacy they do not have any urge to phone home.

I agree that the testing should be ubiquitous but if the device is crooked it is no sense in trying to figure up how exactly crooked it is. Maybe it uses steganography, maybe it is able to detect MiTM devices, some TVsets cease to keep working if the internal memory is 100% filled with pictures of what are you watching so no extra knowledge about the crooked device is useful if you have already agree to have Pavlik Morozov with microphone and videocam right in your bedroom.