When I open a new deck of cards and have them shuffled by someone in the audience, 90% of the time they will comment that they’re slippery. That’s where this gag comes in.
When they comment on the cards being slick, I take out a little caution sign and set it on the table. That gets a laugh, and it’s a gag that will introduce the prop. I like using a gag to introduce a prop, another example of this is my Bodega Coin Tray. Also, when you use the prop for a gag, it serves a purpose and is less suspect later, since the audience thinks it’s already fulfilled its role.
What happens is that during your card tricks, at one point, the signed card appears under the little sign (like card under glass). Then later, you say the card is under the sign, but it’s not; however, the sign has changed to say the name of their card! Then, a moment later, the signed card has reappeared under the sign again!
I’m having a lot of fun with this little prop!
-Louie