Wirelessly posted (BlackBerry8703e/4.1.0 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/104)

One of the things this thread brings to light is the unfortunate recent trend of many restaurants to print two white (duplicate) credit card slips, instead of the two-part, no-carbon-required white and yellow slip. When completing the two-part slip, the customer leaves with an exact copy of the original charge slip, making fraudulent alterations to the original easy to detect. With duplicate original slips, the restaurant (or server) is free to claim that the diner mistakenly wrote a different amount on his copy of the slip. If alteration of the original were skillfully done (say by converting 1's to 4's or 7's, or by converting 3's to 8's), I'm not sure how the credit card company would resolve such a dispute.