Ok, so a few months ago I performed this for my older brother (almost 18). I did it as I normally do and then he said "oh I know how you did it." My stomach churned waiting for the response. "The holes were already there, but covered by a trap door type flap." Phew, so far so good. "The coin knew where to stop because the sharpie had some type of magnetic ink." I started to crack up so hard. All of you who know how simple the method is realize how funny this method is! Thought I would share the story.
Adam

Well it is funny, the crazy ways people think up of how you did an effect. The only one I hear time and time again is for colour monte. I always hear somebody think the card changes the face with temp.