No. Absolutely not. But in the case of the miserable 6.oh no, they weigh out weather to chase comebacks or just put a new bullet in. And even in that case, there have been comebacks. Heck on the dyno sheet that comes with each crate, there's a recording of crankcase pressure IE, blow by.
Back when I was struggling with a couple 6.9 Navijunks that used oil at an unbelievable rate from new, I followed the FSM procedure to check crankcase pressure using a water manometer. I set the RPM as prescribed, and unclamped the line to read the pressure. I never got a chance to get a reading because it blew the liquid out like "Old Faithful". I will never own anything Navijunk-Intrashnational again.
I'll say again that the 6.9 & 7.3's are turning out to be the good ones.
Certainly compared to 6.0 and 6.4, the 6.9 in my 82 F250 was almost bulletproof, except for the glow plug system. The addition of an aftermarket ATS turbo also livened it up considerably. Unfortunately, the layout was such that replacing the slow plugs and/or controller very couple years also necessitated removing the aftermarket turbo…lol.