Well well well this is all very close to home.
I have just this week grounded one of my students, a bit further into his thirties than I am, for being a f

ing idiot in our club aircraft.
A Skyfox is not built to do stall turns and derry turns with any pilot at the controls, least of all a know-it-all rich boy from The Land with his 40 hours.
However, landing it on a polo field
while a polo game is in progress watched by 150 people is possibly the most reckless thing I have ever heard of in an aircraft.
What are the guidelines for an instructor faced with this kind of student? I wonder if his 6-month grounding will make any impact (given that he admits his actions but he will not admit that his actions were wrong).
"I learn better by myself - always been that way"
"It might be illegal but what if I was caught in a mountain wave? I would need to know what to do!"
"I know what I'm doing"
"If a Gazelle can't stand up to that then it should never have flown in the first place!"
"... oh well basically I was bored flying the Gazelle anyway..."
Frankly his conduct is an offence against the Civil Aviation Regulations - a six-month grounding is only the thin edge of the wedge considering we could have his certificate pulled and go on to push criminal procedings with CASA.
Yet, like Mr Durden, my wife and I have probably lost a friend and tonight that weighs heavily on my mind.