My two cents When I go snowboarding, Surfing, waterskiing cycling , play, cricket and soccer. I run the risk of breaking bones drowning impaling myself knocking myself out, getting hit by a car, falling of a cliff etc. So I have a health insurance and life insurance policy and I have written a will.
When I travel overseas im at risk of catching various diseases being treated in a dodgy thridworld hospitals, being kidnapped murdered incarcerated etc so I get travel insurance.
When I partake in these activities, these are acknowledged risks and I have to accept the possible consequences. If i don't like the possible consequences they I don't partake in the activity. Huw runs a good event he's not dodgy he says clearly on his website that you need personal insurance as the race isn't an MTBA event so as long as people read the event info everyone knows the score. To echo the sentiments of another poster I have been to plenty MTBA sanctioned events that have been dodgy.
As far as the Aus champs, theres more than a few Aus marathon champs out there and to be honest out of the 1500 people who will enter the event about ten are a chance of winning and the rest i would suggest aren't too fussed.