The FTC has just settled a case with Vizio, saying that the company has been quietly capturing pixels from their smart TVs, matching those pixels to databases of content, and selling that information (and corresponding IP addresses) to advertisers. It appears to be possible to turn off this "feature", but I'm still not really confident that my information isn't leaking out and being used in ways that I don't want.
I want my TV to communicate with other devices on my network. For example, I like to use Chromecast to cast from my laptop to the TV. But I suspect that the TV doesn't need to directly communicate with anything off my network (except for the occasional system update, which I don't mind opening up for). Would it be effective, and generally reasonable, to simply set my firewall to block outgoing requests from the TV's MAC address, for example? Should I generally be doing this (or something like it) with other devices that I need on my network but don't want communicating with the outside world, like my TV's tablet remote? Are there any other steps that I should take to ensure I'm not broadcasting personal data in such obvious ways?