Sally was a cashier at a grocery store that Kevin McCallister visited while he was on his own.
When she saw Kevin walk up and start placing items on the conveyor belt, she was more suspicious than concerned that he was there by himself, but checked him out anyway. When Kevin casually asked her if the microwave dinners were any good, she said she didn't know, and he replied with "I'll give 'em a whirl" while looking through a magazine he had found on the rack, and she smiled (as though impressed with his wanting to try something new).
Finally, she asked him if he was there alone. Kevin dismissed her question calmly, prompting her to quiz him on where his mom, dad, and siblings were, where he gives her false answers. She then asked him where he lived, but he refuses to tell her. When she asked why, he replied in a serious tone, "Because you’re a stranger."
- In the Home Alone trailer at the store scene, the Cashier's boss is questioning Kevin, not herself.