It was a good performance, but I'm a little skeptical. You couldn't have switched the napkins, because there are no wrinkles in the napkin from crumpling for a false transfer or shuttle pass, or any extra folds for it to fit in your pockets. And you never go near your pockets at all. Something tells me that they were kinda in on it before you started shooting. Not all of them, but maybe one that planted the napkin during the time before the filming began.
It was a great performance though, keep on amazin' Draven!
Cheers,
Casey Rudd