As far as other evidence that is allegedly found in caves or on suspects that are taken into custody, that's certainly dubious and requires us to trust that the government is telling us the truth and we all know what their "word" is worth. If they find a video or piece of evidence in a cave, it could have just as easily been created in a CIA studio or lab somewhere.
In fact, that's something I would expect them to do, regardless of who is guilty of the 9/11 attacks. That's just something that they would seemingly do to drum up support for whatever agenda they want us to go along with. We already know that they did something similar to get us into Gulf War 1 and it is also similar to what they were doing to get us into Gulf War 2.
I would actually be very surprised if much of the evidence supposedly found in caves or hide-outs in Afghanistan/Iraq were not fabricated by our government itself. That's just the kinds of things they do and they can pretty much count on the public guided by the media to not ask any serious questions or look into it past simply believing what they are feeding us.
Take for instance the supposed video of Bin Laden, where he admits to 9/11. The Bin Laden in that picture and the Bin Laden that we all love to hate, look different in various aspects. Another red flag is that Bin Laden had already publicly denied involvement in the attacks. Now, some people might say, "of course a terrorist is going to deny guilt" and "we can;t trust him, he's a terrorist". While that's all good, it isn;t really probable. Can we trust him? Absolutely not, however the very idea of terrorism is for the terrorists to take responsibility for their attacks, otherwise it would be pointless to commit them in the first place. They all commit these attacks to achive some kind of political goal and you can;t achieve that political goal if you deny that you even did the attack. With every other terrorist attack, you had every two-bit terrorist group stepping all over each other to claim responsibility, yet with 9/11, Bin Laden completely denies involvement.
There are also other seemingly fake Bin Laden videos, where his beard appears to have been colored and his robes look like a cheap holloween imitation of known Bin Laden clothes. The crazy thing about this is that Bin Laden wouldn't have colored his beard and the poke in the video really looks nothing like Bin Laden... again. It really does look like a cheap hollywood imitation of Bin Laden himself, yet the video "surfaced" anyway and we were all spoon fed it as reality.
So as far as evidence that the government produces seemingly out of thin air, I tend to take with a huge grain of salt, especially when that "evidence" sends red flags up. We know the government is dubious and we know that they have no problems lying to us. We also know that they are generally good at deception and use it as a stalwart tactic to push forward with their agenda, whatever that agenda may be.
Back when the CIA was fighting the Soviets, I believe that their deception was focused on the Soviets and sometimes "sharpened" on their own people, Americans. However, since the fall of the USSR, I believe that the main focus of the CIA is to decieve the American people. So when before, the CIA was focused on decieving the Soviets, they are now turned inwards and decieve the American people.
That's my 2 cents anyway.
--airspoon
edit on 19-10-2010 by airspoon because: (no reason given)

