Originally Posted by Bart

I don't believe terrorists will settle for a theoretical possibility. They not only want to make absolutely sure that their acts of destruction are successfully carried out, but they also want the terror that comes from the use of explosives. They want the visibility that comes from a punch to the nose as opposed to the anonymity that comes from poisoning a drink. Being able to take credit is just as important as the deed itself. Otherwise, a government investigation could easily conclude that an airplane was downed due to a mechanical/electrical failure (and, if you really want to get carried away with this and jump into the conspiratorial aspects: the government could use this to mask terrorism by blaming it on mechanical/electrical failure). Either way, terrorists want us to know that they did this. A bomb does that. A gun pointed in someone's face does that. A plane flown deliberately into a building does that. A mysterious crash does not.