The problem with a video like this is that it can be edited very selectively. I would bet, the *several* times he missed, he just did not mention the slip of paper - notice how even these spectators forgot about it until he mentioned it.
Often, when I am just in a casual situation and there is a deck of cards - not even standard playing cards - I will boldly name a card that I know is in the deck and dramatically turn over the top card. I am wrong about 80% of the time. But those few times I am simply lucky it is AMAZING and completely floors those with me.