As other posters have already commented spinning should be part of the ppl syllabus.
It was when I did the PPL (1978) and we happily spun the C150, often with a 'flick' entry to ensure it span rather than spiralled. Don't think I'd do that now except perhaps if it was an aerobat and we had 'chutes on. As Ghengis says, every once in a while a normally docile spinner will lock into a hard-to-recover spin.
I've done a few decades of aeros and probably hundreds of spins, and you soon realise that despite a similar entry technique, not all spins are predictably similar. I have been lucky in that all mine were recoverable without too much bother (flat spins in the Yak not excepted!) but it doesn't take much imagination to understand why some very experienced pilots spin-in.
I'd happily aerobat the Chipmunk (gentle basic 'Sunday afternoon' aeros) without a 'chute, but these days I'd think twice about deliberately spinning it without one.