Interesting question isn't it? It is a common experience for most all of us and yet, very few ever give it much thought.
Many stores have electronic monitors at their doors watching for shoplifters and reminding the absent minded to pay.
But some retailers go further, putting a person between you and the exit.
Costco is famous for this. Company policy is to check everyone's receipt when leaving the store. Wal-Mart is known for greeting nearly everyone going into the store, and it also greets a few going out, by asking to see receipts. Over at Best Buy, there are receipt checks, too.
Most consumers we spoke with accept and even support receipt checks.
"They checked your receipt, does that bother you?" asked 7 On Your Side's Michael Finney.
"No not at all," said a customer.
"No it doesn't," said another customer.
"I paid for it, so it isn't a problem for me," said another customer.
We've even had consumers tell us they were saved money because of a receipt check policy.
"A couple of times they checked my receipt and they found I was overcharged, so I went back and got money back, said another customer.
"Really?" said 7 On Your Side's Michael Finney.
"Yeah, yeah," said the customer.
But not everyone is thrilled. Why?
"Because at that point the stuff is mine. It is isn't it?" said another customer.
"Absolutely it is," said Finney.
"They are looking in my bag at my stuff," said the customer.
And he is not alone. Consumer Action's Joe Ridout has heard similar complaints.
"It is very understandable that some people feel very insulted to be treated like a potential criminal after they have potentially been loyal shoppers at the store for many years," said Ridout.
So fine with it or not, here's the question: can the stores do that?
"They can certainly ask your permission to see the receipt in the bag, but that is all they are doing; asking your permission," said Golden Gate University Professor Rachel Van Cleave.
"So you can say 'no',?" asked Finney.
"Yes," said Van Cleave.
Stores do have a right you don't have it is called the "shopkeeper privilege." It goes back hundreds of years to English common law. If a shopkeeper has reason to believe you stole something, he has the right to detain you until the authorities get there. But here's the rub: They have to suspect you not everyone who walks into their store.
We asked the stores about their receipt check policies.
Costco says the receipt check does work to reduce loss, while protecting both the store and customer. Wal-Mart told me it focuses its checks only on items not in a bag, a TV for instance and on items that set off the electronic alarm. Best Buy says its policy is to randomly check receipts and at times focus on particular items.
"I think a lot of shoppers don't notice it, but deep-down they feel it," said Consumer psychologist Kit Yarrow.
Yarrow says even if the receipt check is widely applied, stores could be driving a wedge between them and their customers.
"It doesn't matter if you do it to everyone. Each individual is having it done to them and it doesn't feel good. It feels like you are a suspect," said Yarrow.
The warehouse clubs have it in their membership contracts that they can check. So if they ask and you want to be a member you have to comply. We asked Wal-Mart what it has trained its workers to do if you refuse and was told, they let you walk on by.