Not correct at all. If the weather is crap, no matter what country you might be in, you fly IFR and use the published procedures. Do that, and you won't hit anything.
The other big killers, icing and strong winds, are probably well known in Oz as well?
SPIFR is clearly less safe than having a pair of pilots on board, for many reasons. The trouble is that often the travelling public are not aware of the risk, or don't think to ask about a second pilot. It is unlikely that any charter company would offer the second pilot themselves for a private charter.
And the CAA exists solely for our safety? No. I think not.