I'm super pissed. Went to Italy, turned off every possible toggle that could result in data or voice charges on ATT. Here is the recap...
My phone:
nexus 5
Android, Dirty Unicorn custom ROM
ATT service
settings:
Mobile Data toggle was OFF
Mobile networks--> Data Roaming setting was UNCHECKED (meaning off, not allowed)
I made a few calls using Google Voice while connected to the Hotel's free wifi. I even checked the wifi statusbar symbol to see that the data was going through there and not the cell service. Well, I come back home and all those calls were charged. How do you figure?
I'm so pissed about this. I want to blame ATT. But technically speaking, it looks to me like it might be a Google/Android problem because my suspicion is either those toggles don't work or there's something very tricky about what those toggles actually do...like maybe it turns off web browsing but not voice calling or something idiotic like that.
I also just tried this back at home, I turned off Wifi, data mobile, everything and made a call...and the call went through! WTF!?