I think Enron is actually a good example of what I mean. I maintain that any generally competent professional can have any legitimate accounting practice explained to them. "I don't get it, tell me where these numbers are coming from," will pretty much suffice. Enron's audit committee simply failed to ask the questions (due to laziness or conflicts). Enron's special purpose entities were sitting in the SEC filings waiting to be found by anyone. As soon as the WSJ reporters asked about them Enron started to implode. The SPEs did not make sense and they fell apart without much more than "wtf?"

Needing financial engineers on your audit committee is a giant red flag that your financials don't make sense.

http://www.amazon.com/Days-Reporters-Uncovered-Destroyed-Cor... (Probably not worth the read. Enron short nags WSJ reporters about WTF SPEs in Enron filings. WSJ finally asks Enron and gets gobbledygook instead of explanation. Boom.)