Airline security procedures can be hugely annoying, but this is a reminder that they're not purely theatre. In the first seven months of this year, US Transportation Security Administration found 821 firearms in carry-on luggage, and the vast majority — 691 — were loaded.
I haven't seen comparable figures for Australia, but our much tougher gun laws and lower population suggest it wouldn't be remotely near that number. Indeed, if someone tried to take a loaded gun in hand luggage, I'm convinced it would be headline news. In the States, it's close to a four-times-a-day occurrence. That's a frightening reflection of US gun culture, and a reminder that no matter how ludicrous you find liquid restrictions or how worried you are about where body scanner images might end up, people do try and ignore obvious rules and take deadly items onto planes.
Commenters on the TSA blog were quick to point out that the number of firearms discovered represented a tiny proportion of the overall number of passengers. That's true, but irrelevant. You can argue about the lethal potential of toothpaste, but no-one is arguing over the lethal potential of a loaded gun. No-one needs one of those on a plane.
TSA Year To Date Report [TSA Blog]