Although maybe that just makes for better television... ;)
The backstory is that the magician in question (Kostya Kimlat) did a trick that Penn & Teller also do, and he did it more or less the same way they do it - except that at the end, at the part where P&T do the sleights that make the trick work, in Kimlat's version the effect was already done because he'd done a different sleight, earlier, about five inches under P&T's noses. It was pretty glorious.
The trick: https://www.youtube.com/watch?v=SCFXV6o7cro
Penn talking about it: https://www.youtube.com/watch?v=MuKail7Jwwg
Edit: I think the actual trick starts at 3:49, when he asks Teller to insert his card, either face up or face down. The move at 4:04 finishes the trick and it's done.
1. a few face-down cards on top to make it look like it's still mixed,
2. all the face-up cards plus Penn's card, which went in face-down,
3. all the face-down cards plus Teller's card, which went in face-up.
I have been watching a lot of his videos since then. I doubt I'll ever learn to do any of his tricks 100% but I find his commentary on the social aspect of magic very interesting.
He's also moving a card from one side of his body to another. Later he's moving a card back the other way. My bet is that his vest has some sort of mechanism for moving cards. He moves very awkwardly while doing it, so he's certainly doing some complicated procedure we can't see. He could of course be throwing the card, deflecting it with the insides of his hands or otherwise creating a very curved path, but that's just barely plausible.
Anyway, this guy's Dex score is insane.
He did a demo of his skills at TED: https://www.ted.com/talks/lennart_green_does_close_up_card_m...
For impressive street magic performance, there's Cyril Takayama.
That plus they only get half a minute (usually less) of discussion time to figure it out.
Have a trick that could be done in several different ways. P&T propose one method, and if that wasn't the way you did it, then you win.
When P&T actually make a guess about an original mechanism, sadly Teller either whispers it or draws it on some paper that they then dispose of in some suitably flashy way. (He's usually right of course!)
I've watched the show a few times and I don't know how carefully detailed the rules of success vs failure are, but on a few instances, Penn and Teller announced they had a fair idea of what tricks were being done but couldn't really place it in an acceptable order or say the how/when.
So even if Teller is the magic encyclopedia, he can be fooled, it seems.
The winners are most often low-profile professional magicians who make a significant income consulting for the famous ones. Inventing and selling tricks is an important revenue stream for many magicians.
So they come on, do some trick that they invented in secret and worked on for years, and give P&T that same childlike sense of awe and amazement that the rest of us experience almost all the time. It's the best part of the show.
Like this guy: https://www.youtube.com/watch?v=LyZp4sPqBAI
[0] https://www.reddit.com/r/IAmA/comments/3d5wlc/hi_im_steven_b...
Given that these exist, I wonder how many magicians with a signature trick got it from a consultant instead of inventing it. Are a few people creating all the world's magic acts?