Okay, I understand how wifi calling works. But what happens when you are connected to wifi but unable to access internet? Will the phone work? For example, there are times I'm at the airport, and my phone automatically connects to the wifi. However, the airport requires that I watch a 30 second video before internet will work. Before I'm aware of this due to a desire to browse, I have no idea that my mail is unable to fetch new info. This is because the phone is actively connected to a wifi network, and therefore tries to use it to refresh info, but internet is unavailable. In this type of instance, would the phone default to wifi calling, even though there is no connection? In other words, would the phone stop working?