I think you might be talking about two different failures here. I know of several Cummins that scored #6 (the text book filter failure) and when the technician called STAR, they were advised to replace the engine and return it complete with filter attached. DC and Cummins do a joint tear down and if the piston cooler nozzle(s) are plugged, they attempt to recover from the filter manufacturer.
WhiteKnight's parents truck sounds like a gasket failure. And judging from the numerous posts about this truck, they are quite rare.
Now comes the sticky part, and the part that was probably not handled so well. The filter that was on the truck when it failed was not a MOPAR part. (now settle down and stay with me).
Yes it is an approved part, and yes it is nearly identical to a Cummins and MOPAR part (reference previous TDR filter comparisons) but never the less, it is/was not supplied nor warranted by DC. From a strict legal standpoint, DC had no obligation to handle this under the warranty.
Now in a perfect world, DC should have got together with Cummins/Fleetguard and worked out the problem between them just like in the plugged cooler nozzles. The hope is not to place the customer between the responsible parties (assuming the customer did everything correctly). We all do a great job of second guessing what we would have done in every instance, but unless we are there, that is not so useful.
After reading all the posts about WhiteKnights parents situation, I personally think there is a much bigger lesson here than oil filters, stealers, and manufacturers. The bigger lesson is to handle difficult situations with calm persistence and patience (they had more than me). It is obvious they were raised to respect others, and in doing so, they sure gained my respect.