If you're running into the grocery store just to get a quick drink or snack, self-checkout machines can save you a ton of time. Add a few more items to your list, though, and they are just plain annoying. When they actually work how they're supposed to, self-checkout machines can make your shopping trip more convenient, but those instances are few and far between.
Sometimes you have to scan an item ten times before it's recognized. Other times the touchscreen is so scratched up (probably by angry customers) that you can't press a button without practically punching it. And am I the only one who's constantly getting yelled at to "Please place items in the bagging area?"
Want to make these quirks work to your advantage? If you've ever thought, "These things must be pretty easy to scam," you'd be correct. Some stores have shut down self-checkouts altogether because they lose so much money on people cheating the system, but others like Kroger and Fresh and Easy are embracing and expanding it with scan-as-you-shop devices, which probably wouldn't be that hard to scam either. But let's talk about regular self-checkout scams.
Now, I am in no way advocating that anyone actually go out and steal from stores, but here are some of the most common (and clever) ways that grocery store "hackers" use to get more bang for their buck in self-checkout lines.
One of the simplest tricks is to switch the label of the item you're buying with something cheaper that's of similar weight. It works well with produce because you usually tell the machine what you're buying. This is especially appealing for people who want all the advantages of organic food without the price tag. Some people just cut a bar code off of a cheap item they have at home and take it to the store with them, then put it on the item they want to buy.
Several store managers have also talked about the "banana trick," where thieves will scan expensive items like steak, but tell the machine it's weighing bananas.
A manager at Wal-Mart says that even employees do it, and that the reason it works so well is because as long as customers are scanning something, it usually doesn't look suspicious. Which brings us to our next point...
Have you ever seen a security tag on food? Probably not, which is why it's so easy to get away with not scanning grocery items. Some thieves will scan one item, then put several in the bag. Others pretend to scan the item with the bar code facing away from the reader so that it looks legit if the attendant is looking. Some are even gutsy enough to just leave items in the cart and walk out with them, which is easily the riskiest, but people get away with it.
Using weight to price items seems like a pretty foolproof method, right? Not the case. The scales in self-checkout lines are not always state-of-the-art, so sometimes all it takes to throw off the weight is placing an item close to the edge rather than the center or holding it in your hand while it's being weighed to make it feel lighter to the scale. Some people will also overload the scale so that it can't get a reading at all.
The most sophisticated grocery store hack comes from DEFCON (of course). Brad Threatt used the DEFCON 18 Badge to create a barcode emulator that let him enter an item's code into the badge, scan the badge on the checkout machine, the walk away with something much more expensive than he paid for.
You can find the code for the emulator here.
So, the next time you're standing in line at the self-checkout machines, take a look around and see if any of your fellow shoppers are taking advantage of any of these tricks. And if you decide to try any of them for yourself, well, you didn't hear it from me!