I not not disagree about GPS error. Given the right circumstances and lack of knowledge a GPS can certainly lead you astray. GPS error is one of the many errors (map error, datum error, compass sighting error, etc) we are confronted with in wilderness navigation.

But they did not have a GPS and I think of a GPS as simply part of a good wilderness navigators toolbelt. In my opinion it could have been helpful to tell them that they were at least going away from there trailhead, not getting closer. In fact they were in the "Wrong Province" (state) and heading on a water course towards the pacific ocean, not towards the prairies.

Navigational panic, like any other form of stress induced panic can set-in, hopefully in a survival situation you will recover enough to recheck your tools and look at where you may have made mistakes and correct those errors.