My guess:
Latched on to strongest signal .... Verizon allowed until it checked carrier whitelist....or something along those lines.
Project Fi is supposed to use T-Mobile, Sprint, and US Cellular networks *only*.
US Cellular roams on Verizon.
Those are the carrier's they use. But all carriers have roaming deals with each other. It's not odd to be on Verizon if there is nothing else available.
I never could get a straight answer from Google about that.Yeah, but I don't think that applies to Project Fi and it is certainly not the way Project Fi describes their service. It is supposed to switch between T-Mobile, Sprint, US Cellular towers and, if none available, then try Wi-Fi. As I said above, it is *possible* that T-Mobile has a roaming agreement with Verizon in the OP's area, but I am not even sure about that coming into play for a Fi customer.
Yeah, but I don't think that applies to Project Fi and it is certainly not the way Project Fi describes their service. It is supposed to switch between T-Mobile, Sprint, US Cellular towers and, if none available, then try Wi-Fi. As I said above, it is *possible* that T-Mobile has a roaming agreement with Verizon in the OP's area, but I am not even sure about that coming into play for a Fi customer.
The goal of any cell service is to never leave a customer stranded. Fi has roaming agreements. That's what roaming means. Using other carriers towers when that's the only or best option.
Fi does not have direct roaming agreements - at least none that they advertise. "Roaming" for Fi means switching between T-Mobile and Sprint towers to find the best signal.
However, if T-Mobile or Sprint has a roaming agreement in a given area, then - apparently - that agreement filters through to Fi customers.