The Feds tried this with truck drivers, failed miserably in congress when going through normal policy making procedures. No testing for truck drivers. It seems the FAA medical chief is too busy writing his AME newsletter to have his proposed policy vetted by the legal departments, especially before disseminating it to the public.
We all hate politics but I'm thankful we live in a democracy where idealistic individuals can not institute unilateral decisions without true policy making procedures.