[richtazz]

How about a retractable one, like the maintenance guy keychains?

They actually make them short on purpose to prevent just whay you suggest. This forces the driver to be within eyeshot of the pump handle in case the auto-shut off fails so fuel doesn't shoot everywhere.

I have always rolled my eyes at all the warning signs at gas stations, until I witnessed a massive fire caused by a cell phone first hand. A guy was pumping gas at a station across the street from me, and the whole station lit up in a massive fireball when he answered his cell.
He had an obnoxious ring tone that caught my attention. I looked up just as the fireball ignited. I actually felt the heat from it, and amazingly, the guy was treated for minor burns only and no one else was hurt.