It happens. Your six-pack of Snapple is rung up twice and you are overcharged.  Or you silently notice your cashier overlooks a $10 bottle of conditioner while ringing you up.   Is it your lucky day? What is your obligation to the person or store making the mistake?  The answer? It's complicated.

When you are overcharged it's obvious what to do. But what about when you are undercharged? Is it just assumed you will do the 'right' thing?

If you are the type of person who watches over the cashier like a hawk, chances are the price doesn't ring up higher than you'd expect.  If the cashier accidentally rings up an item twice—you are on it. I know as I've seen both mistakes happen, and yes, I am that guy who notices.

But what would happen if you watched one of your items come up at a lower price? Or an item didn't ring up at all? Would you tell the cashier? We all know what the right thing to do is in theory. However, it isn't always that simple. Here's why.

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When Did You Notice?

When you realize something is amiss is key. Is it when the cashier is ringing up the purchase, when you're in your car, or  when you get home? What you do depends partially on when you figure it out. If I notice it in the store before I pay, I'll bring it up

But the moral line in the sand begins once I am in the parking lot, or when I reach home.

How Much Money Are We Talking?

I'll be honest: If I've reached the parking lot or my home before noticing the mistake, I'm less likely to go back and correct it. If the item was relatively inexpensive, I don't feel like I should have to waste my time. After all, large stores do budget for things like this to happen, and they roll the cost of these errors into the prices of the items you buy anyway.

But if it’s a larger ticket item, I'll generally contact the company to see what they want me to do— If they want me to come back and pay for the item, I'll tell them I'll return it the next time I am at the store rather than making a special trip. If it’s a huge mistake I'll get out of Dodge.  Just kidding.  I'll go back the same day.

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What to Do Depends on the Business 

I strongly believe in supporting small businesses whenever it makes financial sense to do so. For that reason, if I notice any error after shopping at a small business, I'll tell them right away– even after I've made it home – to see what they want to do.

Small businesses operate on much smaller margins, so a few errors could make a big difference in their bottom line.

What If You Made the Mistake?

What should you do if you forgot to put an item on the belt for the cashier to ring up?  For the purpose of this article, we are assuming this is an oversight.  You made the mistake.  Fix it.  Simple.

Another common place you can mess up is at a self-checkout lane. Those fickle machines don't make it easy. You could  ring up an item incorrectly or not ring one up at all. Even here, it's your mistake, as much as it is tempting to blame the store or put it in the ‘no one will ever know' category in your head.  The point is, you know.

Deciding what to do if you're undercharged for an item  isn't as easy as it seems. Our time is valuable, and fixing someone else's mistake…  Let's face it.  We are busy and time is a precious commodity.  Almost as precious as honesty.

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