....but, the goal isn't catching violations of regulations. It's stopping actors with bad intent.

There was no epidemic of "plane knife fights" or "accidental pistol discharge in planes". Catching incidental weapons that weren't going to be used for harm is basically zero value.

All of the value comes from stopping people with bad intent from having weapons. If 95% of them can get through, then that's a very bad system.

In other words, I don't think you've correctly identified signal vs noise.

I disagree. The TSA has no mandate to determine intent - the organization was created to stop those with bad intent (and others) by enforcing regulations on all travelers. Maybe that isn't a good approach, and the high level goal is misaligned with the TSA's goal, but it is the current approach.

There was no epidemic of plane hijacking, either.

I have no data on the intent of people taking loaded firearms or black powder on planes (or knives in teddy bears,

Saying that 95% of people with bad intent can get through is unsupported by the statistic OP linked.

My point here is not that the TSA is great (I personally think it is pretty useless), but to suggest that single statistic is insufficient to demonstrate that the TSA is useless - you also need something indicating probably nothing bad would have happened had the TSA not confiscated all the currently banned stuff.

There absolutely was an epidemic of hijackings, in the 1970s. Then new laws were put in place banning weapons from planes.

That's the system that was in place up until 9/11, and it was run by private airport security. The TSA was a response to that.

But it wasn't the only conceivable response. Changes to private security screening rules would have been another option. The TSA isn't just there in a vacuum. And if people who try to sneak items past it can succeed, then its mandate isn't very effective.

Part of why another 9/11 hasn't happened is that terrrorists know that people know that hijackings can be very deadly. So people wouldn't be so passive anymore. The 9/11 hijacking was done with box cutters. That feat couldn't be repeated again, even with box cutters on the plane.

https://www.vox.com/2016/3/29/11326472/hijacking-airplanes-e...

If we fill out the statistic by saying that the TSA has a high success rate in confiscating items from people who aren't trying to hide them, but a 4% success rate in getting them from people who are trying to hide them, that works out to an overall failure rate of 96%.

We only care about trying to take these things from people who are hiding them. Inconveniencing innocent travelers is a cost of the TSA, not a benefit.

But loads of the stuff the TSA confiscates is hidden - it's probably just hidden because the TSA is really annoying, and people want to take their e.g. pistol to their destination.

No sane person would pack a handgun in carry-on baggage on purpose (the potential hassle if discovered is just too big). When stuff like that happens, it's usually either because people aren't aware or forgot that they're not supposed to do it - might sound strange, but it really happens - or it was a mistake while packing.

By hidden, I wasn't referring to guns just left in bags. The TSA calls it "artful concealment" - stuff like guns taped to steel plates (for X-ray shadow) or knives stuck in the bottom of deodorant. Maybe those people just forgot it, but that's a pretty weird thing to do at any time.

I don't see how sane plays into it - either they are sane and accidentally have a gun in their bag, or they are insane. How can you filter by sanity?

Point is, probably most of the people with guns, swords, etc are not malicious, but I haven't seen any statistics on that, only this 95% cited over and over again.

How often does that happen, though? I can't even recall last time I heard of a case of someone deliberately trying to conceal a gun or a knife in luggage.

198 artfully concealed items found in 2017: https://www.tsa.gov/blog/2018/01/29/tsa-year-review-record-a.... That's pretty extremely rare, given the number of people who go through TSA screens ever year.

I'd recommend reviewing the link though, as that number includes things you might not think are deliberate attempts to hide stuff (swords in canes?).

And our best estimate of their rate of taking hidden stuff is 4%. The fact that they catch a lot of stuff doesn't mean they're getting more than 4% of stuff.