Candidates should only be presented for test when they are ready, even if it means increasing the number of hours of training above the minima. The problem is indeed commercial pressure - attempting to complete the training within the minimum munber of hours with a candidate who is either not up to scratch or whose training extends over a lengthy period, is not viable. Countless reasons why people need extra time. Student pass rate should be virtually 100 per cent if the instructor does his job properly.
As examiners it is incumbent on us to ensure that the standards are maintained and that candidates are fairly treated but everyone is an individual and should be treated with sensitivity. Even the burliest bloke can be upset at a poor performance and nervous at being tested. Think what you feel like yourself when tested for something you are not totally comfortable about. As I have said in other places - there is NEVER a place for swearing, bad language or insults in aviation. Please guys save it for the rugger field or the pub. We all pay good money for our training and deserve to be treated with dignity and respect even if our performance is sub-standard.