I've never liked metal detectors - well, except for the ones you use to look for lost items and buried treasure. It's the ones set up as barriers that I don't like.
I've been thinking about why I don't like them and realized that it's because they're Un-American.
The American Justice system was founded upon the then-radical principle of "innocent until proven guilty." It's arguable as to whether or not we're still operating on that principle, but in theory that's the basis.
But metal detectors are based on a presumption of guilt.
When I'm getting on an airplane, if you're assuming I'm a good person who is and will be innocent of wrongdoing then you won't really care what I have in my pockets. There are some things you'll want to warn me about using on a plane - for example the altitude tends to make butane lighters somewhat more... enthusiastic than they are at ground level which lead to more than a few signed nose hairs back in the day.
Now if you think I'm not a good person - someone who's likely to do something evil while on the plane then you definitely want to know what I have in my pockets so you can do your best to keep me from causing any problem.
So I'm not ranting against passenger screening - I think it's a good thing. But I am against the procedure they currently do. It's not 'passenger' screening, it's just a shakedown of the passerby. If they want it to work then they'll need to actually pay attention to the passengers rather than their pockets.
Similarly, when I go to a concert or sporting event I not only think they have a right to kick / keep out 'fans' who disrupt the event and/or pose a hazard to others, I wish they'd do a better job of it. But I need someone to please explain to me why you need to see my car keys in order to achieve this?
Wouldn't it make more sense to
check on me rather than my possessions? If I'm
the upright solid citizen I appear to be then a 1" blade on
my fingernail clippers will not present a hazard
and does not need to be confiscated.
If I'm a dastardly evil sod intent on creating mayhem you can be sure that there are many, many things that I can not only freely bring in past your metal detector but can also obtain inside that will let me wreak great havoc. Weapons are only tools plus attitude. If you don't have the right attitude then you will never be armed no matter what you hold (but you can still be dangerous). If you've got the proper attitude then anything is a weapon waiting for you to use it.
Which is why metal detectors are useless. They won't stop someone intent on doing wrong. At most they'll (slightly) inconvenience them. They may cause the malefactor to not use a gun, but they won't stop them from bringing in bottles of flammable liquid. If I really want to use a gun on the far side of your metal detector then I'll either slip myself and/or the gun past it or I'll just shoot your (usually unarmed) 'Security Guard'.
Metal detectors can really only do one thing (other than annoy): enforce a climate of dependence and helplessness.
And in a country founded on the concept of Individual Liberty that's definitely Un-American.