kat wrote:

How then would one know if the tanks were filled with the wrong type
of fuel?

checking the fuel receipt is always a good start

Most of the fuel receipts I've gotten weren't filled out by the guy on the truck.
Checking them would tell you if the person making out the receipt made a mistake or
if the entire order was messed up, but it won't help if the fuel truck operator
screwed up.

George Patterson
This marriage is off to a shaky start. The groom just asked the band to
play "Your cheatin' heart", and the bride just requested "Don't come home
a'drinkin' with lovin' on your mind".