Network jail isn't a 100% for these -- in their testing, they determined that they could connect to the public Comcast networks that Comcast tries to blanket areas with. So even if you don't let it access your own networks, it will look for other ways to phone home.

No, they did not find this. They speculated that in the future the tvs "could" do that and that there is precedent with other devices. But despite this being repeated over and over as fact, it is in fact not proven to be the case.