It sometimes works out the other way too. When I was a teenager working at McDonald’s, a guy in an F350 ended up coming from across the street at the Amoco station to get something to eat and figure out what he was going to do about his new car trouble. He had pumped 28 gallons of regular unleaded into the main fuel tank of his Power Stroke F350. I immediately went on break, called a friend, we rounded up some gas cans and a rubber hose, and siphoned all the fuel out of this guy’s main tank. I filled the tank in my '71 Chevy pickup to capacity, and my friend topped up the tank in his S10 with what we got out of this guy’s truck. Both our vehicles smoked a little bit for that tankful, but the guy in the big Ford was grateful for us taking this problem off his hands.