There's been a LOT of debate in this thread about whether one particular kind of security makes sense when another type is ostensibly present. And while a few posters have mentioned EL AL, it's not clear to me that the underlying thesis behind that airline's system has ever been brought up.

Airline security, EL AL style, is about trying to cover as many bases as possible, and make up for potential holes by having a backup plan. I'm not going to get into the middle of this nearly one-year old argument about whether we should or shouldn't have FAMs. I do think there's a lot of misunderstanding and misinformation about the rationale for the program, though. So if you really have a strong opinion, perhaps you might benefit from reading something more detailed. I don't know the author of this piece, nor whether he's particuarly reputable. I do know a little about EL AL and its security, though, and what I've seen in the article seems pretty on target.

Strategies for Countering Terrorism:
Lessons from the Israeli Experience

I would draw particuarly attention to the sub-section marked: Commercial Aviation Security. It discusses in some detail, the concept of concentric rings of security.