I've been cashiering for a few years but this was a new one. A young man comes to my register and plops down a pre-made cake from the bakery. He doesn't look high or drunk, but he has an uncertain kind of vagueness to his movements. I ask if he has a store loyalty card. It's not a credit card, just the regular grocery store type of card that gives you discounts on items the store artificially inflates the prices of to get you to use the card.
Customer: "I forgot my wallet."
He hasn't handed the item back to me, he doesn't look apologetic or like he's going to leave. He's just staring at me with his hands in his pockets, so I give him the benefit of a doubt and assume he means he just left his loyalty card behind, so I ring him up.
Me: "If you don't have your loyalty card I can use your phone number."
He gives me his phone number and it goes through.
Me: "That'll be 11.99."
Uh oh. He's still staring.
Customer: "I forgot my wallet. Can you look up my money?"
Me: "Uh... no. You'll need some form of payment to pay. Do you have a credit or debit card on you, or some cash?"
Customer: "No, I don't have my wallet."
Me: "I'm afraid I can't sell this to you, then."
Customer: "Oh. Okay."
He wanders off. I've had people that left their money at home before and had to give the items back, I've even had a person ask if they could just have the item for free, but never someone that thought I had the power to pull up their bank account via a cash register and spend their money for them.