To become a medic you learn theory, starting from basic A&P, for three years with many many many exams before progressing to the supervised clinical "practical" work. I think you learn far more when you start practical work with a sound understanding of the principles involved so Neil's approach sounds sensible to me. JMTPW.
This is the problem, which is a presumption that principles can be easily learned through classroom activities. They can, along with facts and some concepts...but what do these really mean, and what purpose do they have when considered alongside the day to day curricula of plumbers and gas engineers?
The learning of facts or propositional knowledge (classroom learning) out of context or situation of doing, is also a failing of Higher Education, but they seem to get away with it. For example, I chatted to an ofsted inspector for apprenticeships, and her degree was in economics. For vocational learning, the key to its value is in its purpose, in that subject matter learned is supposed to 'relate' to what is done. Without this close integration of training and assessment, of theory and practice, facts and propositional knowledge are quickly forgotten, because it did not form part of a meaningful event for the student.
This is indeed a situation that can be extended to all areas of education, but for vocational education it is dangerous, and reduces the status of practical learning and experience. When trainee gas engineers, talk of getting 'hours' of experience, then we have a problem.
After nearly 30 years I have had to give up gas work because I cant afford to register, do the courses, maintain my analyser, pay my insurance, etc. Back to plumbing for me, out of the back of my estate car, as I can't afford a van replacement either. Professionalism is a distant memory.
