Guys, I think that you are missing the point here!
In order to teach anything (successfully) it is necessary for the teacher/instructor/lecturer to have a substantially higher level of subject knowledge that the level at which he/she is teaching.
I'm sure that you high hour PPL wanabee instructors have an enourmous amount of useful hints & tips that you could pass on to your students based purely on your own experiences over the years.
However, instruct for long enough and your students will inevitably ask you questions which are not directly covered in the PPL syllabus, but are none the less perfectly reasonable questions for the astute student to ask. There are now three options open to you.
1) Answer the question and offer an explanation as to why that this particular example will not directly effect his PPL VFR flying.
2) Tell him that you don't know the answer because you were not trained to that level of theory.
3) Lie!
Guess which is the prefered option?
I'm sure that if you polled a cross section of PPL sdudents and asked them the following:
"Given the choice, would you prefer your instructor to have been trained to a PPL level of knowledge or a Commercial level of knowledge"
the majority would opt for the latter.
In fact, what I shall do this week is carry out just such a survey and then report back to you ( You have my word that this will be a completely unbiased survey and I will not try to influence the students in any way ).