JT I beg to differ; the subject deserves a wide audience as it poses significant threats which all pilots should be aware of.
The Australian theme probably stems from
Perceived Pilot Workload and Perceived Safety of RNAV (GNSS) Approaches.
My experience and informal investigations indicate that GPS approaches have been over-sold as an answer to the hazards of NPAs. In general GPS/VNAV approaches are much safer, but to the unwary there are several pitfalls.
The most significant issue is that most (all) vertical profiles depend on QNH, and thus a simple mis-setting or crew error in crosschecking can lead to a hazardous situation. Several EGPWS incidents involving large commercial aircraft were reported in a recent FSF presentation; although none were proven to be due to GPS/VNAV, the circumstances and nature of the errors would apply equally to GPS approaches.
I comment on an interesting incident involving QNH (not GPS)
here, what if the MD 11 was IMC and it was using VNAV?