Really... first, it's not even a real threat. It's just speculation.
...and even if they did manage to blow one up, the "experts" can't agree that it would be a "weapon of mass destruction" or a "weapon of mass disruption".
IIRC, some middle east country (Iraq?) tested one, but then discarded it because it didn't do enough damage.
It's a good cattle prod though. It gets the masses all up in a lather. Meanwhile, little things like water supplies and cargo containers go completely unguarded.