From this article by the Seattle Times:
An unusually creepy and clever form of identity theft has cropped up in Washington.
Here's how it works: Con artists prowl retail aisles on the lookout for victims. When a customer steps up to make a purchase, the thief pulls out a cell phone and calls the cashier. Posing as store security, the thief indicates there's a past problem with the customer.
Wanting to protect the store, the cashier then requests additional information from the customer, passing along driver's-license and credit-card numbers to "security."
This was an (apparently) isolated incident at the Sears in Shoreline, WA.
Sears spokeswoman Jan Drummond yesterday said the Shoreline incident was the first reported case of its kind among the chain's 870 department stores.
Drummond said the store had started an investigation immediately and was "still working on some aspects."
Drummond also said the store was reinforcing training of all retail employees to maintain confidentiality of information and was instructing them "not to provide information over the phone, no matter who the individual says they are."
The Shoreline cashier acted reasonably under the circumstances, Drummond maintained.
"This is a very clever thing," Drummond said of the scam. "It's very difficult to stay one step ahead of these guys and figure out where they will find the next vulnerability."