Those scenarios can be better tested through simulations. E.g. to pass a driving exam you are presented with a road situation, and given only a few seconds to respond — this completely eliminates the possibility of looking things up on the internet. A similar approach can be used for other disciplines.
> separate wheat from chaff
Wheat can demonstrate/use the knowledge, chaff can't. Why does it matter whether the knowledge is internal or external, assuming results are the same?