i actually know this trick. it's one of those tricks that look great on tv or stage. however it hardly ever flies in front of friends. you are constantly flipping 3 and 2 cards at a time.... easy for the eye to catch at close distance.
i saw the "david blane exposed" special. what a crock. most of his tricks involve video editing. for instance...
blane asks victim to write name of someone special on a piece of paper then fold it twice (horizontally then vertically, but this instruction is edited out of tv show). after name is written, blane takes it and asks if it was written in cursive. blane says "no, you must print" or "no, you must use cursive". he rips up the paper and tells person to write again. all this is edited out.
when he rips up the paper, he makes sure he keeps the corner piece, which when opened up reveals the name. while the person is rewriting the name, blan is in the corner writing the name on his arm with adhesive.
he takes the second paper, lights it on fire, blows it out and rubs the ashes on his forearm revealing the name.
queue victim's tears.