You can break or cause malfunctions relatively easily if you try hard enough and I think this point gets overlooked on a lot of suspension modifications, altering geometry, lifting, leveling etc. The one comment I would make on this is that while Ford’s main testing is going to be focusing on the factory configuration, their certification is not snowflake. They don’t just test can it haul half a ton, they test can the truck haul a full bed of hardwood from temps between Alaska and Death Valley. We probably benefit from this by getting away with some mods that fly under the radar of this sort of testing abuse.
This is 100% true. Ford, just like GM and Chrysler, torture test their products; especially trucks and SUVs. Meaning they subject them to extremes that most owners and commercial users will never see. The entire purpose is to validation, because that type of abuse quickly exposes a weakness or issue that will show up at a higher mileage under normal or heavy use. If an issue can be prevented before it happens by testing at and above the limits, that is a win for everyone. A great example is Ford's Silver Creek test, which is a relatively basic yet condemning durability example. The F-150, Silverado, and Ram all pass the test with the F-150 being the best performer. Toyota's lack of engineering and durability testing in their "Tundra" shows through clearly, as the bed contacts the cab and destroys the body during the test. Very easy to find on YouTube for those interested.
That being said, those durability tests are not performed with modifications present. They don't install 37" tires, suspension lifts, aftermarket calibrations, etc. and then determine the results. Aftermarket modifications are the joker card; there is no way to predict what will happen and no OE is willing to shoulder responsibility for a failure attributed to a modification or part that they didn't sign off on. And understandably so.