Safetypee, we will have to agree to differ on this one. The realiability of EGPWS is not in question but cannot override pilot situational awareness. For instance, A circle to land in CMF we may get a warning due terrain on the base turn, but we know this, it's in the brief, the SOPS cover this,and are visual. With Airbus, again the circle to land can cause an issue if the secondary flight plan is not active and the "wrong" runway is active, again a visual situation. If the Airfield is not in the FMS, the EGPWS does not give the full warnings. In all these situations, we would certainly not pull up otherwise we would never land.. I agree if the cause is unknown then there is no question of a pull up. Incidently, as far as I am aware, Boeing still inhibit the Flap warnings/ gear warnings when s/e.. the current QRH reflects this.
" The essence of the situation is that you don’t know if a warning is valid or not" Not entirely correct, we do in the above circumstances, and it is covered in the brief