Call me cynical, but are we asked to believe that in the many thousands of Hawk operating cycles, this has never happened before, or has, but was never noticed? Given the location of the pin, it seems obvious that the pilot would find it difficult to spot the error, but ground crew are in a much better position to do so, and I find it hard to believe there were not instances in the past when they did.
Yes it had happened before,groundcrew were re briefed after each incident but please take into account that the Reds did not normally use cockpit access steps when away from home,it would be unsafe to assume they had cockpit access steps in use during the subject sorties (anybody know for sure ?)- if cockpit access steps not in use then the groundcrew would not be able to see the SPH area anyway !