We certainly emphasize these issues during our courses - but a lot has to do with the examination itself. There are two distinct ways to grade a clinical procedure - we will call them the "critical error" approach, and the "average error" approach. In the former, the overall grade is given according to the worst thing you did, and in the latter the overall grade is determined by summing the grades in a number of sub-categories, essentially averaging the errors.
I won't here go into the details of deciding between slight and moderate errors, but whether an error is important enough to be considered failing is important.
Let's say you over extend the facial proximal wall AND you underextend the pulpal depth. For the amalgam procedure, if the thickness of amalgam in the isthmus would be inadequate then the lifetime of the restoration is compromised and that is a major, or failing, error. If the facial wall is overextended by .5 mm or so, and the lifetime would not be impacted, then this would be a moderate or still passing error. For some exams the overall grade for the preparation would be failing because there is one major error, but for other exams only the part of the grade associated with internal form is failed, but the outline form category still passes. Overall the preparation could actually pass if other categories had no errors!
We would like to pass the exam, so the "average error" method sounds desirable - but how does Nature grade? In other words, will the preparation pass LIFE? It doesn't really matter how board examiners grade the preparation - what matters is how it will serve the patient. It would be nice if there would be some correspondence. Unfortunately, in the "average error" case there is not - the preparation can pass the exam but the restoration may break and fall out within days. In the "critical error" grading, the preparation will fail the human graders and fail as well in the test of life!
For the now-discontinued California Dental Board Exam - the old Cal Board - the grading was always based on the critical error. The passing rate was somewhat lower than for other exams based on the average error, but the mandate to do better work was paramount.
Interestingly, it is still possible to pass the some board class II procedures even if you damage the adjacent tooth so severely that the pulp is exposed!
Let's work toward having NO errors that are severe enough to compromise the lifetime of the restoration, and then we will deserve to pass our clinical exam and get fairly licensed.