Project Fi Security on Open WiFi Networks

This is a pretty simple question but I can't seem to find the answer anywhere on the internet. I'm sure any Project Fi user can answer easily...

So I understand how Project Fi works with the free WiFi hotspots that they have verified as “fast and reliable.” It connects to them seamlessly and secures it with a VPN. My question is about what happens with other open WiFi networks that are not on Google's magic list. Obviously you would have to connect manually since it's not a "verified" network, but once you are connected does Google still route your traffic through a VPN? Or are you on your own? I'm always weary about connecting to open WiFi networks when I'm traveling, but I'm too lazy/cheap to set up proper SSH Tunneling or a VPN. It would be great if Google left the VPN functionality there when you manually connect to an unsecured network. I doubt it, but figured I'd ask.

While I'm at it, I was also curious about the prevalence of these "verified" WiFi hotspots. Google's Project Fi coverage map shows you the 4G/3G/2G coverage and that is all well and good. But it seems that the important thing from a money-saving standpoint is how often is it going to be able keep you on WiFi vs cellular data. It would be great if they had a separate map (or a layer you could turn on in the existing map) to get a feel for how often you can expect to be on WiFi. Anyone have a good feel for how prevalent these things are really?

Thanks in advance.