Travelling back from Cape Town, and the fascinating IDLELO conference on the African digital commons (more on that later), I had to pass through Atlanta's Hartsfield-Jackson Airport. Apart from the glaring lack of wifi, the airport was notable for an odd addition to passenger screening: As we queued for the TSA belt, there was a foot-testing platform outside, where we could see for ourselves whether our shoes would beep in the screening line.

What purpose does the foot-tester serve, other than to illustrate the paradoxes of so-called security? I imagine passengers complained that they didn't know whether or not to remove their shoes, so someone decided to give them a helping foot.

But if the foot-tester device is accurate (and it'll cause more frustration than help if it's not), then it serves as an oracle, letting good guys and bad guys alike determine whether they're likely to be picked up. I stepped on and off several times without being questioned. A would-be shoe bomber could probably use a more sinister variation: If the machine beeps, walk away; try again later with cooler shoes; repeat until the machine stays silent. The tester makes it easier for bad guys to see the detection devices' limit and tailor their implements of destruction just below that cutoff.

I tend to doubt the value of most of the so-called security measures we're subjected to in airports, but I'd rather see them removed than modified in bizarre feel-good ways. As it is, this foot-tester seems to create more risks than it solves. Have I missed something?