TURBO--by the way how do you prove that the student has done those things when he is dead!
Because you will have documentary evidence from the student records of the student having completed those exercises.
If you also instruct for any of the larger schools, the student also has to fly with a more senior instructor and satisfy them that they have reached a 'standard' which is also another safeguard for the regular instructor.
You can only do so much - follow the rules and be professional -