The only time you can spin inadvertently? Really?
There have been a few postings on thsi to the efect that the only inadvertent spins happen on the turn to finals when there is insufficient height to recover anyway.
I beg to differ.
For me, the most likely circumstance for an inadvertent spin is through disorientation in cloud (whether entered deliberately with an appropraiet rating or accidentally without one).
This does happen, and the ability to recognise the spin - from instruments alone if necessary (and using instruments to confirm or correct visual/physiological cues in any event) - and recover is a life saver.
I am no fan of scaring students off with early introduction of violent manouevres of any kind. But perhaps if a student isn't up to tackling the challenge of recognising and recovering from a spin before the award of his/her PPL (note, not necessarily before first solo!), perhaps another trip or two to build their confidence and understanding of flying would be a better investment than banking another stat of a 'wings award in minimum hours, saving the student's precious cash'.
There are bigger favours an instructor can do than save the stude's dosh!