I've only spun once unintentionally. I was on an early solo check ride in gliders where spinning is (was?) still part of the syllabus. The idea was to stall straight ahead then recover. Due to gross mishandling of the controls the glider spun...
I'm convinced the instructor saw what was going to happen and was prepared. I wasn't and, despite having spun several times, completely froze. The instructor recovered and, to my suprise, authorised me for solo flight. Big lesson learned.
I support Greeners view that knowing how won't mean that you can when it happens unexpectedly. I also fully support the view that spin training (rather than avoidance training) is crucial.