I'm enjoying these little reads about the hisotry of magic and information about magic, without having to know too much, or getting to know "how tricks are done" since I belong to that group that just wants to be blown away by the pure skill of someone
We're allowed to speculate about the tricks behind spoiler tags, right? I can't remember the policy on this.
Joshua Jay's trick was interesting, but I'm surprised Penn and Teller assumed he needed to switch out the deck to get the blank cards. The dealing method shifts a maximum of 17 cards (for the King of Diamonds) from top to bottom, and there's only Jay's word that there are 52 in the deck to begin with (an enormous deck would probably look and feel noticeably wrong, but a 70 card deck?). So it doesn't seem too hard to see how all the cards needed could be combined into a single deck. Obviously that doesn't explain the whole effect, but I'm basically a complete magic layperson (I've never performed or tried to perform a magic trick in my life) and my immediate response on seeing it was how efficient it was in terms of props and a basic mental shape of how it could be achieved. I'm surprised Penn and Teller didn't have the same reaction.
A weakness in the Fool Us format seems to be that the best way to win is to do a trick which seems to have a "known" explanation in an unusual way, rather than coming up with something utterly mindblowing.