Disclaimer: I'm not a professional magician, just a hobbyist, also known as a layperson who knows too much.
This trick fooled me, and with a little bit of practice, it's fooled the people I've shown it to so far. The instructions are very well-written and easy to understand, so a professional magician would certainly have no trouble at all astounding people with it. Personally, I think this trick works very well with a packet of 12 (marked) face cards; have the spectator mix them up and choose one without looking at it, use the secret card markings to know which of the 12 outs you need to produce, assemble the pieces, and reveal the card. You might also like the method in the instructions which gives the audience the impression that they could have picked any card in the deck and not just a face card.
Workers might want to know that you can't perform surrounded (you have not quite a full 180 degrees of working angles) and that reset is quick, but not instant (you don't want spectators watching you reset). The gimmick makes some noise, so shake the box around to mask it.