A dishonest clerk makes an extra imprint from your credit or charge card and uses it to make personal charges.

You respond to a mailing asking you to call a long distance number for a free trip or bargain-priced travel package. You're told you must join a travel club first and you're asked for your account number so you can be billed. The catch! Charges you didn't make are added to your bill, and you never get your trip.

Scam tricks users into 'stealing' - Zdnet.com
The shopper, curious but a bit suspicious about the low price, e-mailed the seller asking for more information. The seller then offered to ship the camera directly to the shopper, no questions asked, no money upfront. Just a pledge to return it, or wire the $1,299, within 48 hours. 

Seniors Targeted by Credit Card Scam - Elder Care Fraud
According to calls received by the BBB, the company attempts to scare consumers by telling them their credit card numbers are available online. "They ask for the consumer's credit card numbers and expiration dates and promise, for a fee of $289, to remove them from the Internet," said Scott Mecham, BBB president. Some consumers say the company is identifying itself as being with a government agency.