The magician explains that he has taken out an insurance policy against failure. After asking the spectator to pick a card from a regular deck, the magician fails to reveal the correct card. After failing to find the selected cards (by wrongly naming them or by cutting the deck at random, and naming a "matching card") he removes an 'Insurance Policy' from his pocket. 
He explains that he is not worried because he is insured for just such an eventuality by his Insurance Company.  "This policy will refund your ticket money or pay my fees, if I can't locate your selected cards !", he tells the spectators and proceeds to read out some of the Terms And Conditions of the policy. These are gag lines that are sure to draw a chuckle, like
"Special "Sleight-of-Mouth" Clause :    This allows the magician to talk his way out of any situation, provided he's bigger than the spectator.
This policy can be canceled in accordance with the whims of the Insurance Company.
The Magician is entitled to a second and third chance to find the chosen card  providing the spectator weighs less than 400 pounds and looks peaceful."
Upon opening the insurance policy to see if he is covered for this, a giant picture of the card is revealed!  Includes instructions.

An entertaining "find-a-card" effect, large enough for the biggest stage, at a very low price.