This represents another problem for people whose cars require premium gas and are at a gas station that has only one hose for all three grades. How much regular are you being stuck with from the previous customer? Is this customer getting short changed by the gas station, and the next customer getting an unexpected benefit (and usually unneeded).
My son has a Sentra Spec V which requires premium fuel and has a relatively small gas tank. He may put in 12 gallons at the most. Todays pumps have much longer hoses than they used to, mounted high so there is probably a gallon or more of regular going into the tank before the premium get to the nozzle. That’s why he only buys from dedicated pumps.