With the shutdown of 5 or 6 refineries I believe I heard yesterday on the radio that northeast is more dependent on the pipelines which of course switch from gasoline to diesel to jet as required so some mix with diesel is perhaps not unexpected
It was either Topgear or Fifthgear who made a segment where they showed what happens when you mix up the fuel types in diesel and petrol cars. I will see if I can find it. Edit: Fifth gear. Here we go:
I'm voting for diesel pumped into the unleaded tank from the delivery truck. The credit card receipt should be enough documentation if the state finds the tank is contaminated.