Let me see if I can summarize this:
"My God, it never occurred to us that evildoers might use knives and box-cutters to take over an airplane and use that to kill thousands of people, so now we'll stop them from bringing those deadly weapons on board!"
"My God, we never believed that evildoers might hide explosive material in their shoes of all places, so now we'll make sure we check everyone's shoes really, really carefully!"
"My God, who on earth could have possibly imagined that evildoers might try to kill innocent people by bringing liquid explosives on board with them, so now we're definitely going to crack down on that sort of thing!"
Your government anti-terrorist agencies: When thinking ahead is just too much like work.