Zug's Credit Card Prank
was widely linked to a few years ago. This is the prank as he describes it: Every time you make a credit card purchase, they're supposed to match your signature against the one on the back of your card. Nobody seems to check anymore, so I tried to see how far I could push it with wacky signatures like "Mariah Carey" and "Zeus".
Now Zug has posted a sequel to the Credit Card Prank
in which he makes his signatures even wackier and tries to discover what he can get away with. He draws pictures of Shamu, diagrams of the large intestines, and musical notes. They're all happily accepted.
Zug's prank is amusing, but I think the reality is that signing the card and receipt only secondarily serve the purpose of verifying your identity. The primary purpose of the signatures is to demonstrate that you've agreed to the terms of the contract with the credit card company. As long as you sign something (doesn't really matter what it is), the credit card company can say that you've acknowledged and agreed to the terms of the contract, and therefore you have to pay them back. I found this out a couple of years ago when I got into an argument with a post-office employee who refused to take my credit card that had 'See ID' written on the back of it
. Turned out that the post-office employee was in the right. If you haven't signed the back of the card, then technically you haven't finalized your contract with the credit card company, and the card shouldn't be accepted.