Because proposed E-15 expanded use may adversely affect small engine performance, like lawn & garden equipment, motorcycles, scooters, ATV's, etc., and will void warranties, the brilliant folks at the EPA have come up with a solution - - limit the purchase of E-15 at the pump to a minimum of 4 gallons!
Like all motorcycles have gas tanks smaller than 4 gallons, or like all landscape contractors only fill their equipment in the morning and don't carry multiple 5 gallon gas cans that get refilled each day! And like all grades of gas have their own separate hoses at the pump so that residual E-15 won't find its way into the wrong engine!
These people must be on crack.
http://www.jsonline.com/business/4gallon-gas-rule-sparks-debate-b86tmno-170272246.html