I don't think that they really understand how easy it is to make a weapon if you have proper knowledge... I mean, most boys/men have tried at some point or another to make a bomb... If I was a terrorist I'd be buying fireworks. A little every year until I had enough to make a really big bomb. And then throw in a little something nasty like magnesium powder or something... I mean any half-decent street thug can make a bomb out of stuff you can buy in a general store.
Terrorist shopping patterns... As if!