In order to enter into or upgrade within the instructor program, everyone must work with either an advanced or master instructor. On my last upgrade, I went to a master instructor and spent 3 days teaching a class with him. I was given a written test to complete in the evening. The test was based on a combination of the BCA rulebook contents, and questions about teaching techniques. (Example: Explain how you can effectively use video analysis when working with students) I was also given a written evaluation of my ability to teach advanced level students, based on his observations while we were teaching the class.
I'm sure that had I gone to another instructor for that upgrade, the test questions may have been different, but still designed to evaluate my ability to teach. Since each instructor, much like each student, is an individual, there isn't a "one size fits all" program.
That being said, I can state that many of us do work closely together. Last year, RandyG and I sat in my dining room, me reading his workbook as he read mine. I saw things in his book that I asked to use in mine, and he asked for copies of some of what was in my workbook. We talk, work, discuss, and evaluate everything we teach. Sometimes we come up with a better way, and when that happens, the word gets passed around. I haven't seen Scott in person in over a year, but I would be willing to bet that his workbook and mine are nearly identical in the material we cover. When we get together, 90% of our conversations are about pool, and teaching pool.
So while there is no mandate to "teach it this way, or else", a good many of us work by concensus to make sure we are teaching the right things the right way.
And whether or not you agree with what we do, you have to admit that, based on the feedback that many posters on this forum have put up here over the years, there must be something about it that works. If we were selling snake oil, don't you think someone would have been on here to expose us?
While I won't mention names out of respect for their privacy, I had a couple of highly ranked WPBA players go through the class, and the feedback I got was very positive.
It may not be for everybody, but it's gold to a large majority of players.
Steve