I'm a new PPG in the USA, and although I wasn't taught in an
"unspinnable" glider, I was taught "incipient spins" in a SGS-233. The
2-33 will spin, of course, but we never did that (probably because of
its age, but mainly because of Schweizer's letter stating not to spin
it). It was thoroughly drummed into me how to initiate spin recovery
when the nose was dropping and a wing was low.

How well did this training work? Well, a few weeks after I got my PPG I
took an introduction to aerobatics in a Blanik L13AC. First up were
spins - and I found my incipient spin training worked practically
automatically for recovering. Based on this experience, I would
categorically state that if I had ever found myself in a spin before
the aerobatics course, I would definitely have gotten out of it
(assuming I had the height, of course).

I don't really see how my situation would have changed if I was taught
in the ASK-21. There has never been any time during my flying career
that I haven't been paying attention to my flying. The danger of
stalling and/or spinning was always made abundantly clear to me, and
the training I received resulted in me having automatic reflexes for
countering either situation. The ASK-21 is "unspinnable"? Wouldn't
matter....

-John