Which servers do you think your Apple or Google smartphones ping to check for internet connectivity? ;-) It's true that apps generally perform reachability tests on their own sites but global reachability checks can still affect the preference of wifi over cellular, for instamce. And the preferred method on Android to check for reachability, unlike iOS samples, uses the phone's checks rather than pinging a host of your choice.
So just for fun I turned off the WAN connection on my router. Effectively, I had no internet access but I do have a wireless LAN with some local devices.
Safari on iOS did not tell me "you don't have internet connectivity", but it did say that servers were unreachable (not surprising) and it let me use local servers without issue. iOS seems to prefer WiFi to cellular when it's available as it didn't fall back during my limited test.
This is the behaviour that I'd expect from the Smart TV. Just because it can't get to Samsung doesn't mean it can't get to Netflix.
When you connect to a Wifi network, iOS checks http://www.apple.com/library/test/success.html to see if you're in a captive portal (and pop up a full screen webview to let you log into the wifi, or cancel to fail out of it)
I imagine if Apple's DNS settings got screwed up or their server was throwing up something other than "Success" due to an error, iOS devices around the world would claim their Wifi needed a login and wasn't working.
