If an organisation provides training for the Instructor Rating and the requirements for starting the course are x then provided that the candidate meets the minimum requirements you are not permitted to block their attempts to complete the course by adding higher personal requirements.
What nonsense! The pre-entry requirements to my FI course are precisely what I decide they are going to be. If I, as an FIC instructor, decide that I will not take on anyone with less than, say, 200 hrs experience post licence issue, nobody can force me to do so. The
Authority is not allowed to set higher requirements than JAR-FCL for issue of the rating but the industry can do what it likes.
Mind you, I won't get much business because the bloke down the road will take on anyone with the minimum requirements and knows a friendly FIE with a 100% pass rate. He also has an 'in' with the Club that Cows is talking about so he can get his proteges unrestricted in no time. And it all gets worse in the brave new world of EASA.