ABSOLUTELY! Think about what is happening here...they are seeing two pips visually slide out of two existing ones on the card and slowly, openly and visually move into place and then being handed the card for inspection. In fact, there's so much to handle that they usually completely forget that the 4 - that they just saw plainly and openly undergo some crazy metamorphosis into a 6 - is now in their hand (I usually have to remind them. It's great

).
!!
I've performed this in public probably a dozen times since I got it and each and every time, after the change finished and they flip over their changed card, the main subject (who was holding the card) has been
completely silent. They have NO idea what just happened. For me, it's great when they laugh at the impossibility of what just happened or scream or throw the cards into the air and run away. But the sense of complete bewilderment in these people's eyes...priceless.
I really do highly recommend this trick. It's a winner, and something that you're likely to be amazing people with for a long, long time.