A pregnant Irish woman was caught with explosives in her luggage, apparently given to her by her fiancé: https://en.wikipedia.org/wiki/Hindawi_affair

> She claimed to be unaware of the contents, and that she had been given the bag by her fiancé, Nezar Hindawi, a Jordanian.

Certain groups perform attacks of this kind.

It's not necessarily because they are backwards or evil or something. They just can't resist militarily, so they go for soft targets.

If the situation was reversed, and there was some kind of hegemonic global Islamic caliphate with an ostensibly unbeatable military, perhaps you would get some random Poles or Spaniards blowing up planes.

People who aren't in groups in those kinds of situations, don't do things like that. Why would they? Why do we pretend that they would?

The thing is that being, for example, Arabic looking or having an Arabic sounding name isn't a prerequisite for being Muslim. So if we started profiling for people that we thought were Muslim, then it would be pretty easy for terrorists to figure out our criteria and just use the most "white-seeming" of their cohort to commit attacks.

If, on the other hand, you randomly select people for additional checking, they can't predict that and can't learn how to circumvent it, they just have to take a stab at an attack and hope they don't get unlucky.

Basically, any deterministic aspect of security is predictable, which makes it vulnerable.