well, my guess is because it's really painfully obvious, and they knew that just by watching it, any magician that wasn't a neophyte would instantly be able to duplicate this trick. Not that they'd want to if they're more into "strong" magic. the exact same thing happened with Indecent or whatever , the trailers never showed the part where they pick up the bag with the card in it and remove the card, because it is so insanely obvious what is going on. what this means is that I really have no idea what the first half of witness looks like, so why would I buy it, unless I was like a lot of n00bs and simply bought into the hype. i'll have to wait until a you tuber submits a clip of themselves doing the WHOLE performance in order to even really see what the point of the effect is. since the theory 11 guys clearly are so ashamed of the first part of the trick that they won't even put it in the trailer.