Well yeah, if you have a lockable cap, then you need the key to start
the van. I have never driven off like M'obeechi, but you never know
what a mere human will do. The best thing to come out of this thread
so far is that reminder to not get back in the car while fueling, by
Robert Keezer. This is a real danger and I do point this out to people
when I see them do this. One good precaution, if you have to get back
in, or just for the hell of it, is to go ahead and touch a good ground
before any fueling.
How about rigging an ear onto the gas cap, which operates a switch
(like we have on our doors) that interrupts the signal to the starter
solenoid? Ha!

Gracias,
                    Miguel