Indeed. My (mandatory) civil engineering courses were taught by a professional forensic engineer. His assertion was that every single catastrophic structural failure was the result of a fundamental design flaw due to some engineer screwing up big time, and he had dozens of examples. In fact, they were actually brilliant teaching examples on many levels -- he'd present a real case and ask us to identify the design flaw. Most structures, if designed correctly, are significantly over-engineered.
I guess will find out which is which for the Superdome.
I wouldn't leave out the fact that it was public construction and lord knows how many payoffs, how much under spec material, questionable inspections, etc., were a part of that deal.