Trust / Safety
I have seen a fair bit of abuse towards security staff at airports on this board, when it is the Government who is responsible.
I agree that the Government should serve the people, and not have police demanding to see I.D cards of citizens, as this is a police state. However the police can demand to know who you are.
However at an airport as long as there is sufficient I.D to get airside then there should be no issue.
Ultimately any I.D system that is making sure that it is the flight crew who are boarding the flight and not unauthorized people is required in a form which works and is secure.