A point that many people seem to miss (and is part of what peeves me off as an airline pilot) is this:
Current airport security screening is designed wholely and soley to prevent people getting through the security checkpoint with the means to gain access to the cockpit, and thus control of the plane, or with other means to bring the plane down.
When I'm operating crew, you can confiscate whatever the hell you like from me - right down to my undies if it pleases you - but don't then allow me to simply swagger into the cockpit anyway! You have, in one foul swoop, just unravelled virtually the entire point of going through the security screening!
When was the last time my ID was thoroughly and closely checked?
Answer: Never!
When was the last time I was refused access to the cockpit because of some contraband item they found at security?
Answer: Never! Though I, like many others, have been pulled up for inadvertent and minor contraband.
When was the last time they checked I was even the pilot who was supposed to be operating the flight?
Answer: In Australia, never! ONLY in the US (and often even then with a precursory glance at the ID).
There is pretty much only one way to ensure that an operating pilot is not going to put in a bootfull of left rudder and full backstick in flight, or thump the other bloke with the (.....insert cockpit weapon-of-choice here.....), or just trick him into getting locked out and then do whatever the hell he likes: Make sure he's done the appropriate clearances, checks, profiling, psych tests, etc, BEFORE he gets up the front.
This means TAILORING the security procedures according to what you're trying to achieve and who you are targeting. Confiscating a freakin' goddamn umbrella from an operating pilot because its point is too sharp is NOT repeat NOT going to save you!! (sorry for the increasingly hysterical nature of this post, but I find it REALLY frustrating that many lay-people and transport officials live in magical fairyland).
