I am the assistant manager at a local chain of pet stores. We have a buyer rewards program on a lot of different stuff, mostly dog and cat dry food, but other stuff too. To sign up for it, we just need a name, phone number, and address. When you come in to shop, you give that phone number/name, and it tracks your purchases towards free stuff. We do NOT take IDs or anything, since families often use the same account: husbands and wives mostly, but whole families sometimes too.
So, this young woman (early twenties at the oldest) came in and grabbed a big bag of dog food. We'll call her YW, and I will be Me.
Me: Did you find everything okay?
YW: Yup, just this please. My phone number for my account is XXX-XXX-XXXX.
Me: Great, under (her name)?
YW: Yes. I think this is my free bag, or I'm close to it. Can you check?
(The account shows when you bought food and how many purchases you need to get your free bag).
Me: Hmm. It looks like you got your free bag recently. This is the first bag on a new program.
YW: That's not possible. I'm positive this is my free bag! Did you computers screw something up?
(Now she's positive it's her free bag. And no, my computer system doesn't really "screw up" that way).
Me: Well, I suppose it might be possible, but it's unlikely. Are you sure you didn't get your free bag last time and just don't remember?
(I mean, I personally would remember leaving a pet store with a $60 bag of dog food free, but that's just me).
YW: Absolutely not. The whole reason I come to your stores is because of this program. I've been waiting and waiting on it, and now it's GONE? Do you want me to never come here again? Cause [big name pet store] sells this too!
(Kind of. And everyone sells this dog food, but only I give it away for free).
Me: Ma'am, do you have any other phone numbers or last names I might be able to check? Maybe a relative used it by accident, or you have two accounts?
(This is somewhat common, as people change names and get new phone numbers. Sometimes spouses have two separate accounts).
YW: No! This is my only account, under my strangely spelled last name, and my old phone number! You guys just gave away my free bag! I can't believe it! I want my free bag!
Me: Unfortunately ma'am, we don't ID people when they use these accounts, because often many people use it at the same time. Do you shop at any of our other stores? I can try to get info from them, see if they have a record of the receipt?
I ended up calling her normal store an hour away. The free bag was given out 6 weeks ago, but the person paid cash for everything else so there was no record of who it might have been. When I relayed this to the customer, it was not pretty.
YW: I can't believe you just gave my free bag away! This food is so expensive, I really needed that free bag! I need my food tonight!
Me: Ma'am, are you sure you weren't at your local store on that date?
YW: You're going to give this bag to me for free, right?
Me: Unfortunately I can't give you a free bag tonight. All of my information shows a free bag was redeemed already.
YW: BUT IT WASN'T ME!
Me: Ma'am, you just said you're not 100% sure. And you said this is your old phone number only you remember and your last name is incredibly uncommon. How is some random person going to just "steal" your free bag?
I ended up giving her 15% her purchase that night with a promise to look further into the problem to get her out of the store.