I think it would be pretty convenient to have the same technology that is now in 'tap' credit cards, implemented into gas nozzles and tanks in your car. The nozzle on the pump would have a sensor to gather billing info, that would be recieved from another chip mounted just inside your car where you place the pump. When your finished some info should be collected by your car: Price paid for gas, how many gallons, date etc. Your car could then compare that info to your...