You miss the point entirely SAS......
You have appointed yourself judge jury and executioner. I suppose you consider yourself a benevolent dictator....
I have seen some shocking standards over time but gentle guidance and common sense works much better than the jack boot. You may never say it to the student but the fact that you have thought it and written it in public will be carried in your demeanour towards your students.
It is not OUR job to make up rules it is not even our job to enforce rules. Instructors are not aviation police.
You may think that you can blend morality into making up your own rules as some sort of validation for your methods.
The fact is that as Instructors we have the responsibility to teach and advise. If an individual chooses to ignore that advice that is the end of it. It is called free will. Once we start on the slippery road of taking away the free will of others where does democracy go?
Ringing around examiners and telling them not to sign is just despicable and an attempt at removing others freedom just because you don't like it.
Like I said before often the poor performance of a student can be down to the approach of the Instructor and someone who performs badly for you may perform perfectly for me and vice versa. If you don't like what you see, you tell them and let THEM choose. Most people that I have come across value the input you give them and will make their own arrangements to improve. They do not need you dictating to them.