[Bigiron]

You know how Public sectors/ Stat board been audit before AGO come?

How it go, first so call " internal audit , they will select staffs from various departments within ownself audit ownself "
Along the way prepare before Officially AGO come audit

First party audit, 2nd party audit and 3rd party audit ( usually this is outsiders) 
But also depends on the integrity on the 3rd party auditor and how skillful he able to find the loophole. 

Therefore all 3rd party need to know bl and the way to ask questions also.