They search people randomly anyway, and they search people if the human operator thinks they see something suspicious. If we can keep the number of searches constant and just increase the probability of finding a knife, it's a win for everyone.
It's obviously not a win if there's too many false positives, but it's worth a try.
If we have X cases where people brought knives onto planes, and no notable incidents of knife-enabled violence in the past few years, what's the motivation for reducing X by half?
I'm sure that some would-be-criminals are dissuaded by the TSA, but that seems to already be working today. It seems like a very reasonable outcome would be no decrease in airline violence/crime, but an increase in taking people's property.
All said, if there is still a scourge of knife-wielding criminals on airlines, I'd be happy to be wrong here. Otherwise, though, this seems like it have a very marginally negative impact on the average passenger by taking away their belongings that they accidentally packed.
Great point! Although I'd think P(knife hijacking)*Cost(knife hijacking) would be much much larger than the cost of knives being confiscated, even if P(knife hijacking) is very small, just given how cheap knives are and how big that Cost is. I think the bigger point is how much the software would cost and whether the reduction in X justifies that expenditure. Also need to consider cost savings of being able to fire some TSA staff. That reduces the theatre aspect perhaps, but maybe not if it's done the right way (I can think of a few ideas)
Joe McRandom is heading through TSA, and is falsely flagged as having a knife by this software.
Because the computer _can't_ be wrong - a depressingly common view among anyone who doesn't work with computers regularly - the TSA agent flags our friend Joe. Joe's entire luggage is then unpacked, in front of everyone present - hope he didn't have anything sensitive in there!
When he inevitably does not have a knife in his luggage, the TSA agent spends way too much time searching for the secret compartment, as well as digging through all the stuff. When there is _still_ no knife to be found, Joe is taken into custody - we've already seen that airport security can be trusted to abuse their power - causing Joe to miss his flight, be psychologically damaged (I'd be pretty shook up after that degree of search and detainment), and possibly lose his luggage (better hope the TSA did a good job keeping track of it, and decides you deserver to have it)!
Is this situation likely, strictly speaking? Over the massive number of TSA agents working and travel being done, I would say yes. All of the negative effects of the TSA mentioned above already happen, a system like this just makes it more likely to be occur for no real reason.
Also, while the average knife may not be expensive, some are. On top of that, many who carry knives form emotional attachments to them, so even if there's no "real" damage being done, there is some amount of harm being done in a much harder to quantify way.
I was going to put a disclaimer because of the risk of sounding cliche/ironic/sarcastic, but figured it was a legitimately good idea so I decided to spare people.
