Source: http://www.engadget.com/2013/09/15/google-glass-bluetooth-tethering-without-data-plan/
An Explorer Edition of Glass is already a pricey piece of tech, and smartphone tethering plans required to give it a mobile Internet connection have only made ownership that much more expensive. However, there's good news for Google's guinea pigs: the latest update to the headgear quietly implemented a way around the additional monthly fees. With XE9 loaded onto headsets, the companion Android app pipes data to and from the hardware, bypassing both the smartphone's Bluetooth tethering settings and extra plan previously needed from some carriers. To match the change, the application's notification icon sports two arrows to signify the flow of info. We doubt telcos will be fazed by this development for now, but we don't know if that'll hold once Glass arrives on shelves and hits the streets en masse. We've contacted Google to find out if the feature will make it to retail units.