From Elmwood Magic and Joshua Jay! 

Joshua Jay's Wonder Wallet Series Continues...

No Card Control No Palming Use Any Wallet Use Any Card  and Yes, It's Signed!

You explain to your audience that a magician is obligated to perform whenever called upon. In fact, it's part of the rules. You show your magic association membership card which clearly states this obligation is real. The membership card is placed back in your wallet and a deck of cards is introduced.

A spectator selects any card and signs their name to the face. The card is openly cut into the center of the deck and the cards are handed to a spectator.

The spectator spreads the cards and in the middle they now see your membership card! You remove the card and explain, “If MY card is in the deck, I guess that means YOUR card must be in my....”

You open your wallet and remove a playing card from within - the spectator's signed selection! Obligation satisfied.