Okay, so this story actually occurred during a register outage.
After I was cussed out by a customer who I wouldn't allow to do a $5 exchange (that we couldn't do because the registers were down) I went to the back to cool off (read: cry a bit.) Within two minutes I was promptly paged back up and this encounter happened:
We're gonna call this customer, a little old lady, Sob Story Lady (SSL for short.)
SSL: [holding a canvas] "Hi, I really need to buy this."
Me: "I'm so sorry but the registers are down. I can gladly hold it for you though."
SSL: "No, you don't understand. My granddaughter needs this for her project for school. She absolutely needs this."
Me: "I'm so sorry. I can call another store and see if they have one we can put on hold for you."
SSL: [starting to tear up] "I don't have time to stop at another store! My daughter is in the hospital and I'm heading there now!!" [Pulls out a wad of bills] "Can't I just give you cash?"
Me: [fully aware I could lose my job for that] "I'm so sorry about your daughter, but there's nothing I can do. I can't take cash; our registers aren't working."
SSL: [crying] "What if I just walk out with it."
Me: "Excuse me? Ma'am I can't let you do that."
SSL: "What would you do if I just walked out with this right now?"
Me: "That's shoplifting. I'd have to call security."
SSL: "Fine. Fine!" [throws down canvas and leaves]
Keep in mind that she also pulled this with me even though she was present in line during a previous lady's screaming fest at me.
I mean, if your daughter was in the hospital and you needed something that bad for her project but you absolutely didn't have time to stop at another store (where I worked we have another store less than ten minutes away) than I am almost positive her teacher would have understood and given her extra time!