You knew this would happen...
Case in point, see how I'm on Wi-Fi. That's someone else's wide-open Android Wi-Fi hot-spot. I was on for but a minute, but the point is that if I wanted to, I could have severely eaten into their monthly data allowance.
People, if you're going to enable this feature on your phone, LOCK IT DOWN. if you don't know how, DON'T USE IT!
