Yes, airport security is mainly public relations. It's the classic case of shutting the gate after the horse has bolted. I don't know if you remember pre-9/11 but the conventional wisdom for a hijack was to keep calm and do what you are told. You might end up in Switzerland or Beirut but you'd probably get out alive. So, of course, a pilot would give control of the plane to a guy who had a knife to the throat of a hostess.
Post 9/11, no captain is going to open the cockpit door to a bad guy with a weapon and the passengers are not going to sit there calmly either. So the whole idea of banning knives on planes was obsolete on November 12th 2000.
And banning the sale of undetectable knives in the USA is going to help how? If they are undetectable, they'd be pretty easy to import.
Post 9/11, no captain is going to open the cockpit door to a bad guy with a weapon and the passengers are not going to sit there calmly either. So the whole idea of banning knives on planes was obsolete on November 12th 2000.
And banning the sale of undetectable knives in the USA is going to help how? If they are undetectable, they'd be pretty easy to import.