Unfortunately, aviation history is littered with fatal examples of people who knew what they were doing, but carried on regardless:
The DC10 had a known weakness, established before it flew, with regard to the impact of an explosive decompression on the floor, and therefore on control lines. But nothing was done, and the aircraft was certified. In service, a problem emerged with the cargo-door latching mechanism, but nothing was done and the aircraft continued to fly. An American Airlines DC10 suffered explosive decompression over Windsor, from a faulty cargo-door blowing off, but the pilot brilliantly saved the day, and still the aircraft remained certified. It wasn't until the THY crash out of Paris with the loss of all souls, that those who knew what they were doing acted. A lot of the current actions being played out over the Dreamliner problems looks suspiciously similar to what happened with the DC10.
And also on the DC10, presumably the AA engineers that re-attached an engine using a fork-lift truck rather than the approved cradle also knew what they were doing.