Pete,
You are jumping to the conclusion that every system is the same as yours.
I will be assigned an examination session having never met, yet alone trained, the candidates involved, with the strict brief to conduct the exercises required and asses the performance I observe.
Of course it would be best if any deficiency in the candidates skill set was recognized and corrected before it gets to the exam, but if the reality is that my job is to asses the performance I am presented with, and that performance is clearly sub-standard, what would you have me do?
Are you prescient enough to recognize any potential deficiency in your candidates and nip it in the bud before they demonstrate it during an exam?