Commonsense has two basic problem areas,
1 - People often do not have a surfeit of sense.
2 - When sense is available, it is seldom common that it should be so.
To be absolutelively honest, if you are a basic wage chimp with a rulebook to follow, then deviating from the rulebook simply because of commonsense is probably not a survival trait. Look at it this way, for those of us who are genuinely paid to think then going through security at a modern western airport affords us a modicum of amusement while we gnash our teeth at the restrictions.
I did, at Gatwick, heading for my Orlando flight with wife and kids once point out very politely that whilst I - a white, late middle aged family man with family in tow, dressed in chinos and a T shirt, had been stopped (shoes off) they had just let an obviously middle eastern man in his 30's walk through with his shoes still on and an anorak (in midsummer) tightly zipped up to his neck. I was told they had to be careful not to be seen to be racist....
I find the TSA folk to be less hassle than the Gatwick people myself, if we applied a degree of commonsense to these checks - bu**er sensibilities - then travel needn't be the pain in the butt it has been for the last decade. Profile the bad guys, and stop this incredibly slow scanning of everyone passing through... we really do NOT need to be scanning everyone.
Troops should be able to walk right through - if you don't trust the people who guard you, then all is already lost.
Dave