Re: Security checks for crews are getting to the riduculous!
I suspect it is all about visibility.
The real checks, that are most likely to make a difference, are intelligence related - it is the non-obtrusive (but actually far more inquisitive) stuff like sniffers in the baggage handling, random phone and Email intercepts, background checks, and so-on.
I've occasionally forgotten about a swiss army knife and had it taken away (to be returned at the other end, phew) when travelling as a pax, and once had to argue the point with an overzealous security official when flying P2 - but my hobby is teaching martial arts! I don't need a 3½" bit of steel to kill somebody - as well as all of the arguments given above.
For that matter anybody can do far more damage with a smashed bottle than a small knife, but nobody is stopping pax taking bottles of duty free on board.
I believe that most airline security is pretty damned good - but, it is important to the powers that be that they give every appearance of being OTT. It's just a bloody nuisance. Maybe LHR could employ some out of work actors, dress a few in airline uniforms, and they can regularly get subjected to very public scrutiny to give this appearance, and save the rest of us.
G