SR71: Although the final waypoint was named "McMurdo", the co-ordinates were written underneath. All the crew had to do was check this waypoint on the chart that was included in the despatch documents, either before take-off, or on the way down. If there was no potential issue concerning this waypoint, then it is not reasonable to expect the crew to check. But in this case, there was a potential issue, if you accept that Capt. Wilson told them that the nav track went to McMurdo Station.
Can't argue with the proposition that AirNZ were far more careless than the crew. So what about 75%/25%?