Yesterday afternoon, I returned to Oslo from a short trip to Flanders. These days, airport security is mostly focused on preventing people from bringing any potentially liquid substances onto the plane, so I emptied the little bottle of water I had before I proceeded to security control. It didn't help though: the empty bottle was confiscated because, as it happens, empty bottles are on the black list too. I'm not sure whether it were the remaining drops of water inside the bottle, or the possibility that I would fill the bottle up with water again afterwards, but I certainly wasn't allowed to take it along.

The present airport security measures are best described as systemized nonsense. The result of the current "war on liquids" may very well be that it has now become easier than ever to smuggle solid explosives onto a plane. Another result is that the metal detectors currently seem to react at such a low threshold that one doesn't need much more than a simple watch to be taken out of the line for an extra check. There cannot be much time left to watch how people are behaving during security control, even though that is more likely a better way to detect terrorists.

As to the liquids, my impression from a few hours of surfing the Internet is that it is practically impossible to blow up a plane using liquid explosives. Basically these kinds of explosives can be divided into two classes: either they are so unstable that one needs almost an entire chemical laboratory to bring them onto the plane safely, or they are so stable that they require a strong detonator which would certainly be noticed at the security control. The present security measures have been motivated more by incompetence and panic – always a bad combination – than by anything else. That some British would-be terrorists had absolutely no sense for practical chemistry does not seem to me a good enough reason for confiscating tubes of toothpaste and bottles of water at airports all over the world.

But let us presume, for the sake of the argument, that there is a case for screening all sorts of liquids, would it then make sense to confiscate empty bottles? None of the people involved yesterday afternoon doubted that my bottle really was empty, i.e. that there was no liquid in it and that I could not do anything dangerous with it on the plane. Actually, you can buy lots of bottles full of water a few yards from the security control. The message I got was that empty bottles were on the list, and therefore I couldn't take it with me. I wonder who put it on the list in the first place. The only thing I can imagine is that empty bottles are forbidden by association: liquids are dangerous, liquids can be transported in bottles, therefore bottles are dangerous too. What will be next? Am I still allowed to carry empty boxes? You never know there may be a terrorist out there planning to smuggle explosives onto a plane using a box…