The production in chain implies the development of a great number of homogeneus goods in the shortest possible time; joining together the potential of workers, machines and timers.
From my customer experience, can tell that I have found massive and homogeneus goods with errors. It was evident the mistake when I tried to change the product (under warranty) and the new product had the same error. Going further, all the series had the same problem.
An hipotesis about this situation, could tell us that if we find an unobservable error in a massive product (something that exceed quality controls), then all the serie might have the same problem.