When inserted into the context of aviation, I find the concept of over-engineering a tad more comforting than what the alternative implies....
Anything less, smacks of risk management, and look where that got BAA last week.
As to reliability, anything, or anyone for that matter, that gets on a bit in years is likely to have a few more reliability issues... sympathy and tlc are the order of the day!
regards from a member of the unofficial rj fan club.