I don't know if it's been posted where the link came from, but these folding tricks have been all over the internet since 9/11. They were even shown on TV for awhile...haven't seen them around as much, but I know they've still been circulating via e-mail periodically.
Not sure that this answers your questions really but........that's all the input I can give.
Thanks.
I've seen the trick before too, but since I don't frequent the jihadi forums, I have no way of knowing whether this comes up from time to time, or if there was a surge of this "speculation" right after 9/11 and then it pretty much died down until today.
I don't like seeing violent images involving DC at this particular moment. (not that any moment is good)