If they can’t see when the sleight of hand occurs or when a swap happens then they might have an idea of how to perform the trick but not exactly sure when the person performed it. That’s them being fooled.
I’ve watched many of the acts on YouTube and you can slow them down to see when it occured.
There’s one with a ring where he appears to move the ring from finger to finger. Then at the very end he appears to pull the ring off his finger. When you slow it down you can see his finger bend down at a very unnatural position that is borderline dislocated. But he then hands the ring over. Now we know he’s using a retractable ring. But he swapped it prior to the end of the act so it appears that he used a solid ring the whole time. P&T don’t know when he swapped it. Slowing it down you can see when he pockets it tho.
I’ve watched many of the acts on YouTube and you can slow them down to see when it occured.
There’s one with a ring where he appears to move the ring from finger to finger. Then at the very end he appears to pull the ring off his finger. When you slow it down you can see his finger bend down at a very unnatural position that is borderline dislocated. But he then hands the ring over. Now we know he’s using a retractable ring. But he swapped it prior to the end of the act so it appears that he used a solid ring the whole time. P&T don’t know when he swapped it. Slowing it down you can see when he pockets it tho.