We all watched the video and thought "perfect trick". The other person supplies the deck, they pick
a card, we don't touch the cards, and then they deal it face down and we say "that's your card."
Kicker if you want, (I've only watched it once), you handle the cards or the last few, and say
without turning it over, "this is your card and it's the 4 of whatever."
It's perfect,
simple, and, yes, you will fool magicians. It's especially effective for the jaded audience of one
or two who aren't generally impressed with card tricks.
Now for his coin from balloon...