Conspiracy theories are easy to make up. It's impossible to disprove them, which is why it sticks. But most of the time they're not proven either. It's like claiming that there's a teapot on the moon. There is no logic in discussing conspiracy theories, being they are theories based largely on circumstantial evidence.

Anyway, a large group of people conspiring to carry stuff like this out, and the fact that they're pretty much human, without having anyone turn rogue...forget it, it's less likely than the WTC attacks being masterminded by George Bush.

It does make a good basis for a movie/TV plot though. Think Prison Break.