My point was mainly.. if its a major problem, it will show when driving it or inspecting it visually. And most inspections are only to do exactly the same as you could anyhow.
Other than physically opening up the gearbox, or other components of the engine (which of course no inspection is ever going to do), I don't see how those things are checked in any other way than simply driving it or checking for very obvious signs by the inspector either.
I don't think they even get it on the hoist to check the chasis condition in most instances, and the tests I have witnessed have mainly been visual and a very short road test. They seem to be very superficial in most instances.
If you were interstate you would at least want some piece of mind, but then again, without you supervising the test how do you know the depth the test has done?? I would never accept an inspection from somebody else without physically taking the car for a drive myself. They could have spent just 10 minutes looking at it, or the owner could have slipped them $500 to give a good report - you never know.