I watched a video recently where a lady showed how many gas pumps use the same pump lines for the filler hose. If a guy fills his car with regular ethanol 87 and another guy comes after him and fills his 1 gallon gas can with non-ethanol 91; he will likely get 1/2 to 3/4 gallon of the E87 because the lines are still full of the old stuff. Only pumps with dedicated nozzle for non-ethanol would be exempt from this. Was an enlightening video.