Back when I worked as a passenger agent at Cardiff-Wales International Airport, September 11th was still somewhat fresh in people's minds (and here we are now a week from the third anniversary) and so we were very, very strict about what went into your cabin bags: no knives or stabbing weapons, but also bizarre things like:
- hairdryers or similar electrical appliances - we were told this was because of the strangulation potential of the cord, but given your belt or shoelaces would do just as well, this restriction didn't last
- nail clippers, for some unfathomable reason (although I did get myself a nice brand-new pair after someone handed them in to me)
- metal nail files, for slightly more obvious reasons
- gas-powered hair curlers, unless the only fuel cylinder was already inserted into the curlers
- corkscrews and bottle openers
- tools, such as screwdrivers, hammers and the like.
All fairly obvious things, with potential for harm. This also explains why virtually all airlines now give plastic cutlery to eat with (so cutting meat that's been a 'steak' far longer than it was a cow is doubly hard) and don't offer sewing kits. I took a few days off and took a flight out from Cardiff to stay with a friend in Glasgow. I brought my laptop.
Typical procedure is to make you turn it on (so it's not just a bomb in an empty casing) but they didn't care. On the flight back to Cardiff the security guy asked if he could inspect the contents of the back. I happily obliged, and as he rummaged through my mouse, power adaptor, I noticed the top pouch. Just visible was the corner of my (like ssd's) mini Swiss Army Knife/corkscrew/thingy from a Christmas cracker.
Somehow, the guy didn't see it, and I was on my way, shaken both by the risk I'd inadvertently run with a 'weapon' in my cabin bag both ways, but also that it had been missed twice despite being in an easily-accessible location. So many things struck me: how pointless confiscating nail files was, how poor security still was despite the terrorist attacks, and how if you were really determined you could get something truly dangerous onto a plane...
...like when I was working and the guard called me over and pointed to the rather large power tool some woman had in her suitcase, clearly visible on the x-ray machine.