SIGHTLESS was designed to give the illusion that the audience has full control of the whole process in the routine. It makes the effect stronger, and the magician has zero chance of doing "anything" at all.
EFFECT: Imagine you introduce a blue-backed deck to your audience and also show there is only one red-backed card in the deck -- you remark, "that is the FUTURE." You ask your spectator to insert the red card half way in her front left pocket so everybody can see it. Then you ask your spectator to shuffle the cards and put them in their front right pocket. You instruct her to grab just one card as quickly as possible from her right pocket as you snap your fingers. Guess what? The card that was freely chosen MATCHES the red card that was displayed in full view in her left pocket from the beginning of the routine!