I had 2 students in a recent OW course who initially had problems clearing their masks, but were otherwise meeting all requirements in the course. After some remediation with the first student, a simple suggestion to switch to a better fitting mask not only solved the problem psychologically for that student, but it also solved the real problem of a poor fitting mask, as well as the problem of not being able to fully clear it.
With both students, I scheduled an extra pool session (on my own time, without extra charge to the students) to give them more practice with this skill. The second student finally succeeded once they reached more of a comfort level and learned better airway control (breathing through the mouth only, not the nose, and keeping water out of the nose). This case was a matter of getting a little anxiety under control through familiarity and repeated practice.
There are usually more significant underlying factors that keep students from mastering simple skills. The biggest one is probably anxiety/fear. Sometimes it's poor fitting gear, getting in too much of a hurry, not breaking skills down in to subskills, multi-tasking, prescription medication, physical conditioning, and many others that are too many to name. For instructors, it's a real challenge trying to identfy underlying causes so the problems can be solved.
Standards require students to "master" skills to the satisfaction of their instructor. I believe in failing a student only if they cannot meet all certifying agency requirements. This protects them from future harm and protects me from legal litigation. It only takes one breath to drown, so there is not much room for error in teaching (or participating in) scuba diving. However, I will work with students to the very limits of my patience, time and resources to give them every possible chance to succeed in a course. It's amazing how much a student can accomplish from the start of a course to the end of a course once they get used to a few basics.
Although mask clearing is a simple skill, it is an extremely important one. It is one skill that may be used more often on a regular basis than many other skills. It can mean the difference between a comfortable, enjoyable dive, or a miserable dive that could lead to panic and accident, or worse.
In regards to requiring students to solve unexpected, fake "emergencies" underwater by ripping masks off and pulling regs out of mouths, I can only say this...instructors are strickly required to teach the standards of the agencies they are certified by. They are bound by these standards that are drilled into their heads. If you teach using the approved and established standards, then your agency and your insurance carrier should back you up if something goes wrong. If you teach outside of, or above and beyond the approved and established standards, then you are usually on your own if something goes wrong.
We are not only taught this in the Instructor Development Course (IDC), but we are also required to purchase and read actual cases involving accidents, injuries, fatalities and the legal consequences and outcomes of these events. I personally will take the conservative side, and not deviate from standards. What others may do are, of course, judgment calls on their behalf, and calculated risks they have to consider.
Just my 5 cents worth!
