There is a mechanism for Costco. When you enter the warehouse, employees check a membership card. Shopping carts that are used in warehouses are large in size and the paths inside stores are wide so that shopping carts pass easily. Conveyor belts are utilized at checkouts. They enable cashiers to check out mass products smoothly. They don't provide plastic bags, so their own bags or cardboards are needed. After that, employees check recipes to prevent shoplifting and mistakes at the cash before exiting the store.  