Well, with respect to your airline scenario - most companies would design along with those industry specifications in mind from the outset.
Even without doing so, considerable reverse engineering can still be achieved. The case of the De Havilland Comet comes to mind - they had to basically redesign the entire fuselage construction from the ground up once they realised the single layer pressure cell was a major design flaw.
I think the De Havilland Comet is actually a poster child for exactly how badly things can turn out rather than a good counter-example. The original mistake was apparently quite small - square windows instead of round. By the time they finally fixed this and shipped a solid and reliable product it was too late. Hundreds of people had died, Boeing and Douglas had entered the market with better planes and ate their lunch. The company died as well. You could make a case with only a little exaggeration that this mistake killed the British aerospace industry and setup the US for decades of dominance advanced technology industries.
Even without doing so, considerable reverse engineering can still be achieved. The case of the De Havilland Comet comes to mind - they had to basically redesign the entire fuselage construction from the ground up once they realised the single layer pressure cell was a major design flaw.