Earlier quoted context omitted.
Do you think having an outside method of examining the source code is advantage enough when the AI can rewrite its source code.
Yes, because examining the old source code allows you to predict its behaviour, including the rewriting of source code . If line 42 says "never rewrite lines 42 or 43" and line 43 says "never kill humans" you would be more likely to let it out of the box than if line 42 said "rewrite whatever you want" and line 43 said "do whatever is necessary to achieve world domination."
This is the halting problem (http://en.wikipedia.org/wiki/Halting_problem), and there is no solution.