The QNH cross check is automatic -- an amber "ALT" warning is displayed on both PFD's if the CAPT and FO QNH are not identical.
Of course, this would not help safety if both crew left 29.92 selected instead of resetting to QNH. Does the presence of such a good system cross check reduce awareness of the need to have an independent check of the actual value that has been set?
Is this similar to taking a more relaxed view of terrain (subconsciously) because MSAW will detect hazardous low altitude; except that it won’t if 29.92 is set by mistake.
And what about having EGPWS and active windshear detection fitted, does this result in a lower level of attention to the associated hazards?
These questions follow on from my interest in ‘safer’ VNAV approaches and also that there may be some indication that mis-set QNH or similar errors are increasing (experience, rumor, hearsay); and these are the errors that go undetected or more likely unreported.