[koz1000]

Given how people stuff their carts, seems like you could easily bury something expensive at the bottom. If the store is super busy the receipt checkers probably won't disassemble your whole cart.

[copperx]

But how? Run to the warehouse again after the cashier has charged you and bring an item and sneak it into the cart? Sounds very hard to do.

The only plausible thing is to steal at the self-checkout, but the receipts are different and cause more scrutiny at the door.