Nate Johnson is an idiot.
Your battery still works fine when you run out of gas, especially since you've been driving long enough to deplete the gas, and have thus charged it. Did they really not bring a car charger for any of their cell phones on a long-distance road trip?
And who runs out of gas?!?!? People who are that stupid and irresponsible don't deserve the privilege to drive. You should never let your car get to the point of having the warning light on since it's not great for your car to drive with minimal gas, but if it does come on, PUT SOME GAS IN. If you can't afford gas, don't drive.