Lets say you're the captain of a flight, and you have just learned the plane is 10 pounds over max gross weight? What do you do? Every single captain I've flown with would just fudge the numbers and continue on with the flight, knowing that 10 pounds will not hurt anyone. At the same time, I do not know of a single captain that would admit doing anything other than canceling the flight when presented with this scenario during an interview.
It is a great idea to be honest and all that, but a lot of times you just can't be. Would you say its best to keep it real by honestly fessing up to doing illegal-yet-hardly-unsafe stuff during an interview, or telling them what they want to hear?
The problem is you just can't always be that perfect example of the aviation cherub. There are many times when you have to fudge it, or else screw over a lot of people over what amounts to nothing. Its absolutely impossible to go through your career without doing some dirt along the way. Furthermore, since there are so many regulations, it's very easy to get caught up in "dirt" without ever even approaching "unsafe"
This is what I hate about interviews so much. There are so many situations where it's basically lose/lose. Your Boeing 737 is 10 pounds over max gross. Do be the perfect aviator and cancel the flight, screwing over all those passengers over nothing, or do you be the perfect aviator and get it done safely, yet still break the law?