Jack Ciesielski, who publishes The Analyst's Accounting Observer, found this comment by Chris Cox on AS5 intriguing: "The SEC and the PCAOB expect a change in the behavior of the individuals who are responsible for following these new procedures. To that end, the PCAOB's inspection program will monitor whether audit firms are implementing the new auditing standard in a cost-effective way that is designed to achieve the intended results. And the SEC, in our oversight capacity, will monitor the effectiveness of the PCAOB's inspections." So you've got the SEC watching the PCAOB watching the audit firms who are watching the companies. But it is so very subjective. Can you really enforce a new top-down approach? Can you really enforce a principles-based mentality? There are many who think that the new AS5 isn't really going to do much because it lacks specifics. When push comes to shove in an audit, you might expect the auditors to revert to what has worked in the past--no matter how awful for the client. No one ever got fired for keeping their billable hours high.  

For more:
- here's Cox's statement [1]
- here's a copy [2] of the blog post