It's kind of older news apparently, but I follow this board pretty closely and don't recall anyone mentioning it before. I was just in a Starbucks in Northridge, CA (which is not a Google Fiber city) and GF has already replaced attwifi. It's interesting from a brand roll-out perspective (all 7000 Starbucks in the US are supposed to go GF).
Google Fiber only provides the actual WiFi connection in Google Fiber cities like K.C. Outside of Google Fiber cities, like Northridge CA., Level 3 provides the network connectivity and equipment installation but the service is delivered under the Google brand. In places like Northridge, the Starbucks WiFi service is not delivered by Google Fiber's network and that's why they advertise "WiFi service up to 10X your current speed" in these Non Google Fiber areas and "WiFi service up to 100X your current speed" in Google Fiber areas.