security screening
Perhaps this thread (which originated on another tiny website that is not allowed to be mentioned here) is best summed up by stating that a lot of the time, effort, and money directed to checking whether the cockpit crew are carrying nail clippers, or Swiss Army knives, would be far better spent on checking the more likely areas terrorists can easily penetrate....checked baggage, galley supplies, cleaning equipment, refuellers - the list of people, and things, that are permitted airside access with a more or less cursory check.
As Few Cloudy (and many of us previously) has stated, Tech crew could walk on naked, and still do the same damage as Muhammed Atta did on 911. But for the FACT that crew members are there to check OTHER crew members, in addition to checking themselves.
And prior to that, the regulatory authority and the approved medico will also have assessed the crews' mental, and physical, condition.