The biggest problem they have is people putting DEF in the fuel tank...
which i could see this or gasoline being very hard to prove what they did, most common rail systems should not fail, but im sure ford will try to deny warranty for whatever reason but personally i would fight the *** out of it and make them PROVE what actually caused it. IDS will show you how many key cycles, miles ect with the water in fuel light on, if its never been on how can they say anything about it? and blaming aftermarket fuel tanks is silly, unless they can prove that the inside of the tank is rusted, coating is coming out ect, and even then the filter should catch that. Thats why its there