I have read most of the posts and tend to agree with the majority. We need security screening and it needs to be seen to be thorough. This makes potential terrorists think twice and we might even be lucky and catch one who is trying to bluff his way through.
It is a boring job and so is open to mistakes due to operator fatigue. (Imagine 2 hours over the Atlantic with no autopilot.) This means you have to recruit the type who doesn't bore easily. This means they are not employed for their brains. The problem then is you cannot train them to use their judgement, so they have to react in the same way when they find something.
I was due to fly out to rescue a plane and so was carrying my toolbox as hand luggage because we were flying out on the relief aircraft. (No loaders) Of course the box showed as a black rectangle so a physical check was carried out. Of the 2lb hammer, selection of screwdrivers, pliers and cutters, the only thing that was nearly confiscated was a Stanley knife. It took 3 people all explaining the situation to get my knife back.
Moral of this story? Don't go hi-jacking with a knife, use a hammer instead.