When you leave CostCo you have to present your receipt and an employee carefully looks it over and looks in your basket and then highlights it -- you can now leave the store.

I accidentally did a security audit. I handed them the wrong receipt (from Menards). They stared at it thoughtfully, looked in my basket, highlighted it, let me leave.

So, ya. They're not actually looking at the receipt at all. #l33thaX0rz