Note: There is a posting in another forum about a Ford owner that mistakenly put 3 1/2 to 4 cups of DEF in his diesel fuel by mistake. The DEF downloaded granules throughout his fuel system. Damage: $14K covered by insurance. They had pictures of the filters and fuel system, and it was the damnest thing. To do the repairs, the whole cab had to be lifted completely off the truck.
I know some other brands have the DEF filler neck in other places than Ford. But when you deal with diesels, you must pay very close attention anytime you're refueling or adding DEF to an engine.