"No terrorist is going to base his plot on getting a gun through airport security if there's decent chance of getting caught, because the consequences of getting caught are too great."
That wouldn't seem to apply to lone suicide bombers, since the worst consequence for them comes if they don't get caught. And if they were caught, they could at least detonate in the airport and cause some havoc.
A suicide bomber doesn't need to worry about airport security at all. They just need to figure out when the airport is at its most crowded and stand in a check in line and detonate their bomb.
A wearable bomb can only kill (say) few dozen people, even in a crowded area, but the same bomb detonated on a 747 could kill 400.
It could also allow them to gain control of the aircraft (maybe, depending on whether they can persuade the people on board that they aren't planning to crash it into anything).
Suicide bombers generally aren't rational folks who multiply "number of infidels I can kill" versus "chance of being caught" though. And we should be thankful that they aren't so rational.
I don't know why they're not already doing this. In fact, they might be better off still just walking in with machine guns and shooting as many people as they can. You could probably mow down a lot at a crowded airport.
It makes me think that we're doing a pretty good job of keeping most of them out of the country in the first place. Otherwise I think we'd be seeing a rash of smaller scaled, highly targeted incidences like this.
But if you are a lone suicide bomber, getting caught IS the worst consequence (dying when you explode your bomb is optimal.) Rather than achieving your goal, in the worst case scenario, you're caught and prevented from being able to attempt it again.
The author is absolutely right. The non-dangerous category is part of a knee-jerk reaction to simply "do something" rather than to do something effective.
I assume the worst consequence, from their point of view, would be humiliation.
Either a humiliating failure to detonate, or a humiliating detonation that kills only them, and slowly, like that guy who tried to drive a truck bomb into Glasgow airport.
That wouldn't seem to apply to lone suicide bombers, since the worst consequence for them comes if they don't get caught. And if they were caught, they could at least detonate in the airport and cause some havoc.