Paul,
Keep us updated on the outcome. It is most likely that you would
not hear from the individual who used the pump after you. I agree that
it hardly cost you anything but your time to post here. At the
minimum, your experience will help others to be more careful in using
self service pump.
Years ago, I accidently left a barely used $50 copy card in the
copying machine. I had nobody but myself to blame for loss. I am
pretty sure that if I had known someone who did the same thing before,
I would have been more careful.
When we first started using the self sevice pump, at one time, we
forget to reset the meter and was quite concerned in seeing the meter
added up our purchase to the previous one. We went to talk to the FBO
and was told not to worry. He explained to us that although the meter
was not reset, the system had a way of recording the exact purchase.
We checked our credit card billing later and found that this was the
case.
Although most self service station let you enter the estimated
dollars or gallons that you want to purchase, I recall having used some
which did not offer this option. Again, most stations issued a
receipt but I have come across some that did not give any either. In
any case, we will be more careful when hanging up the pump.
Thank you for posting your experience here.

Hai Longworth