I did the CRI course for SEP back in 2006, principally so I could check out fellow club pilots and conduct 2nd year revalidation flights, so that the FI could concentrate on ab initio instruction. I wouldn't say that the course was dangerously short, but then I had 500+ hours at that stage. It consisted of 25 hours 'teaching and learning' ground school plus receiving and 'giving back' long and pre-flight briefs. There's also 3 hours flying, as I recall.The flight test took half a day and consisted of delivering a long brief, then a pre-flight brief, then about an hour's flight covering bits of the syllabus, especially stall recovery, slow flight etc. I think a new PPL would struggle with the test after only 3 hours instruction, but probably the ATO wouldn't let you take the test if they didn't think you'd pass.
In the ensuing 12 months, I suppose I did about 20 hours actual 'instructional' flying so hardly setting the world alight and I certainly didn't charge for any of it, even though I had a CPL.
What was good, though, was when I subsequently did the full FI course, I did feel some confidence that I was somewhat suited for the role, though I found the course itself pretty tough.
Latterly, LAA 'coaches' are I believe now checked out as CRI, very helpful when they might be the only person experienced on a particular make of aircraft. It is also a way for very experienced aerobatic pilots to pass on their knowledge to new people entering the sport, without having to do the full FI course.
TOO