You always leave the huge Costco store with different emotions, as you are secured with a six-month supply of toilet paper but bothered that you don’t have anything for a meal after spending a hefty amount of money, SFGATE reported.

As you exit the warehouse store with your cart, one of Costco’s well-known greeters at the door looks at your receipt. The measure, unlike the common assumption, is not because of shoplifters, San Francisco store’s general manager Kevin Heuer cleared. He said Costco is not facing any shoplifting problems.

“It’s pretty simple,” he said. “We want to make sure they’re not getting overcharged and they’re not getting undercharged. It’s not to target shoplifters. Invariably that could happen without someone paying for something, but if there’s an extra item in their basket, that’s not their fault. That’s our fault. Sometimes checkers forget to ring up items placed on the bottom of the basket.”

In the retail business, exit greeters are usually deployed to check the customer’s items according to their receipt. In a day, about 10 to 12 receipt audits were done by the store and in most of these instances, customers realize they paid more for the items and receive the excess money back to their pockets.

“We want to offer customer service,” says Heuer. “They also check to see if something such as movie tickets was purchased. If you buy those, you have to go to the customer service counter desk to pick those up. We don’t want customers to get home and realize they don’t have the tickets.”

The receipt-checking at the exit is not new. In fact, it has been there since 1983 when the first Costco welcomed customers in Seattle, Heuer said.

“It’s our most effective method of maintaining accuracy in inventory control, and it’s also a good way to ensure that our members have been charged properly for their purchases,” Costco said on its website.