Having attended a few of these refreshers over the years, I would liken them to that old bromide about sausage-making and politics -- no one really desires to see either made.
True, you get to disassemble and reassemble whatever the respective company has to offer; perhaps learn a few new insights; but we never even had to tune anything that we had worked upon; and there was one torque wrench for the whole class. We simply saw it demonstrated by the instructor, on a single test box -- not that I was that enthused about pressurizing the scratched-up crap that we were given to service, in the first place.
Most of the students were novices, and spent a good deal of time futzing with the tools, much like that hominid, fretting over the bones, in
2001.
Confidence, in their handling of your gear, even afterwards, could be expressed at almost nil; and people wonder why there is such a burgeoning DIY community? The accounts of botched regulator service on this site, alone, are legion.
Most questions were directed toward "hey, look it up" in the online manuals, which anyone can really do; and I've read more useful and interesting insights on this site's DIY threads, over the years, than at any four-hour seminar that I've ever attended -- and we now have the luxury of
@rsingler's ongoing seminars, on regulator repair.
What could be more better?