They're not exactly burdened by extreme sports injuries, most surfers, for example, are injured crossing roads, in car accidents, or at work falling off roofs, etc.
Citizens have an obligation to act responsibly when they partake in broad social contracts such as shared health care and insurance. Such a society must regulate access to areas of extreme danger (disused mines) to stop mentally unwell citizens from endangering themselves but more importantly endangering their fellow contract holders.
The whole inland gold belt region is filled with abandoned shafts and it's rare anyone falls down them.
What's the cost benefit in fencing off tens of thousands of individual pre existing shafts and to what degree of robust security construstion do you recommend? More to the point, what's the tax payer out of pocket cost for that?
You don't appear to have actually thought this through in any pragmatic sense.
Growing up in the Kimberley it was all Bull Buggies, Broomstick choppers, Quarter Horses and dirt bikes, all intrinsically a wee bit risky - but good practice for "grown up" geophys surveying in custom STOL crop dusters.
3:54 B taurus indicus begs to differ! (no oysters on the menu plz?)
The guy who taught me to swing a Brunton was over four times my age, and whenever we were hiking in to a site he led us in: this basically meant we young vegetables would be frantically scrambling up to a nearby ridge so we could spot where he'd got to, only to eventually notice him waving cheerfully at us from the next ridge line over.
'Wee bit risky" is right, keep your head on a swivel and don't be on the quad bike when the irate bull flips it and all is okay.
Your leading surveyor was very much our father when we were in single digits .. four hour long walks across rugged landscapes and down gorges with him as a barely visible dot waaaay up ahead.
He's a lot slower now approaching 90 .. but can still split wood and shovel a tonne or two.
They're not exactly burdened by extreme sports injuries, most surfers, for example, are injured crossing roads, in car accidents, or at work falling off roofs, etc.
( source: one of https://en.wikipedia.org/wiki/Fiona_Stanley conversations back in the day )