Once wrote a complaint to Home Depot for beginning the policy of opening and searching boxes being purchased in the checkout. Told them they should hire more security instead of treating every customer like a thief. They responded with some policy bla bla; shop at Lowes now.
Lowe's does the same thing these days, as does Miejer, Penney's, Sears, TJ Maxx and Walmart. We all have to. Being subtle in checking the merchandise is key to NOT making each customer feel like a criminal but it HAS to be done.
The problem is that customers will pick up a big box of something that costs fifty bucks and re-fill it with thousands of bucks worth of small high cost items.
I can usually spot them, though. They have a number of "signatures." Sometimes they are in pairs or threes, not Large groups, though. They have a look out or a person to distract the sales floor.
They often have their booty in a cart with the UPC up so that it can be scanned without touching the carton. Most people, even those who really want to help the poor checkout kids, pay no attention to where the UPC code is located until they get to the check out. BY ensuring that the UPC code is pointed outward, no one has to move the box around and discover that it rattles and it is four or five times as heavy as it should be.
If no one spots this signature, then they can literally walk out of the store with thousands of bucks worth of brand new products, still in original packaging that they only paid fifty bucks for. Great game!