RichardKenner

Except that there's a significant risk of being caught unless the first TSO is bribable and that's hard. I think people on this forum tend to greatly underestimate the difficulty of implementing plots that rely on "insiders". Those are indeed viable if the opponent is a national intelligence service whose operators are trained in how to approach and select people. They learn how to do so in a way that won't cause suspicion and they also learn how to fit into a society. But it can take years to be successful in that sort of task because of the very real risk of being reported by people who aren't willing to cooperate, especially in this day and age. So they have to move very slowly, deliberately, and carefully.

I don't think that terrorist groups ever had that capability, but it's nearly impossible that they have it now given the focus on operations to degrade and track communications and money slow, both of which are essential to the success of any such long-term operation.