I'm assuming there are no manufacturing defects. I'm assuming proofing the sample barrels validates the manufacturing process, a process which does not produce inherently flawed barrels. That's my logic and there's no flaw in my logic I use to choose to not proof my barrel. The only possible flaw in the outcome is not in not assuring the barrel is safe to shoot because I've proofed it myself, but rather it's in trusting the manufacturer to not produce a flawed barrel. There is a small but not zero probability my decision logic leads to a bad experience with a defective barrel. But, frankly, I think the probability is so small that it can be ignored; at least I'm willing to do so given the constraints I operate within. And I recommend anyone else make their own decision whether to proof or not to proof. I'm not advocating one way or the other.
As a former professional pilot, I have quite a bit of experience dealing with weighing the probabilities of undesirable outcomes vs. the desired outcome and deciding on a course of action that produces the desired outcome when eliminating all protential undesirable outcomes could only be done by not achieving the desired outcome at all.
No one is or can ever be perfectly safe at all times and in all circumstances.