Every TV ships with a non-unique secret key and an agreement with some major internet service provider which specifies that accounts using that key will gain network access but only to a specific list of IP addresses that host or proxy firmware updates and advertising content.

[edit - to be clear, I'm not saying that this is what Samsung is doing, I'm just describing a plausible way how this might get done]

Everyone has said stuff like this but there has been zero proof of TVs connecting to wifi like this on their own. If you have that proof please share it.

>> Wanna bet [Broad Company Wifi Networks] are or will be used by your smart TV > What makes me think this will never happen...

The comment suggests that the behavior of auto-connecting to wifi is infeasible for technical reasons. My comment and the one below it show that this is technically feasible.