Comment by weli
1 day ago
This is pretty dangerous. At least in my country the displayed price must be honored and they cannot refuse the sale.
1 day ago
This is pretty dangerous. At least in my country the displayed price must be honored and they cannot refuse the sale.
Usually the advertised price must be honored, because it may have brought the customer to your store.
For prices displayed on the shelf-label inside the store the law is usually not that strict (YMMV), as a shop-owner can refuse sale on check-out (otherwise I could put a pricetag on e.g. a shopping-basket and the shop-owner would be legally required to sell me the basket...).
Besides, most shops I've seen (in Europe) already moved from Infrared communication to RF (NFC or proprietary), for centralized shelf-label management without handheld devices. So all this study (and the underlying reverse engineering of the IR-protocol) might do is probably accelerate the transition from IR to RF-based ESL...
> Usually the advertised price must be honored, because it may have brought the customer to your store.
This is not the case for groceries in Massachusetts at least. If there’s a discrepancy between the tag’s price and the scanned price the store must charge the customer the lowest of the two: https://www.mass.gov/price-accuracy-information
I suspect this law does not apply in cases of fraud. If not, simple tag-switching would be rampant.
7 replies →
I recently learned that in some cases fines of mispriced goods were very low, leading to companies repeatedly failing tests - and over/undercharging their customers.
https://www.theguardian.com/us-news/2025/dec/03/customers-pa...
That seems shocking to me, but I guess I live in a country where the prices on the shelves are "final" (with no need to add taxes) and I think it would be immediately obvious if I'd been charged the wrong price for goods.
It definitely varies by jurisdiction, but the register price always loses to any printed price in the US states I’ve lived in. This is a protection since retailers have used pricing mistakes to unfairly profit. Watch your receipt like a hawk at the dollar store[0]
[0] https://www.theguardian.com/us-news/2025/dec/03/customers-pa...
Very much depends where. In QC, if it rings higher than tagged in the store you get the first one for free and the next ones at the lower price. They take it VERY seriously as a result and will take the tag down while they make a new one to ensure nobody else gets a freebie.
Stores hate giving the product away and pricing errors are much lower in my experience.
How is the transport medium changing anything?
To me this is about having protocols that are suitable so not anybody can write to these labels without knowing a store secret or using replay attacks.
> How is the transport medium changing anything?
it's mostly about efficiency. IR based, an employee needs to physically walk around. RF based, place a transmitter or two in the building and the system now works fully automated.
2 replies →
In your country merchants are not obligated to honor fraudulently altered price displays.
That may not be true if the faked display contents are reasonable. Price labels on shelves are leading: https://www.consumentenbond.nl/juridisch-advies/rechten-bij-...
Supermarkets all throughout my country have these labels add "35% off" to any goods that they need to remove from shelves (either because they expire soon or because they want to replace the product with something different). That's done outside of normal advertising campaigns, just in the price tags on the shelves (and the digital systems, if they actually work).
Supermarkets here are already on thin ice because they frequently do not charge the price listed on shelves already, without malpractice.
Of course, if you happen to have a cart full of wrongly discounted stuff that someone needs to go out and correct, the store will probably look through security footage. If you play the game well and can make it look like a glitch in the system, a store would probably not bother, though.
No it's not.
We've been able to take a price sticker off one object and put it onto another for a very, very long time.
It's not really a new issue and current law should already cater for it.
It's crazy that supermarkets invested in tags without even basic authentication. Hopefully they can sue the manufacturer for the cost of replacing them with moderately secure ones/reflashing the existing tags with secure firmware.
The extreme lack of cybersecurity for something as essential as (often legally binding) price indicators should shock the entire industry, although I feel like it comes to no surprise to anyone actually working on integrating these things.
That law probably wouldn't apply if someone brought their own label printer into the store and put their own price tags on to the merchandise, which is essentially what this is.
Probably mostly dangerous for the user, or are people routinely writing their own price signs in the store and then "buying" it for less? Walking up to the lot at the car store and crossing out some zeros? Don't see how this would be any different.
Back in the day people used to swap/edit price tags a lot. Also making fake coupons with the same knowledge. It was a pretty common and easy form of shoplifting since all barcodes used to do was just encode the pricing/discount information.
This is why the stickers have cuts in them, and why the barcodes cross-reference other things.
What they do is swap bar codes, or they code organic fruit as regular, or they "forget" to scan in the self checkout, but yes.
So it's just stealing with extra steps.
1 reply →
This is a big reason why retail product barcode stickers (not barcodes printed directly on a package as it comes from the manufacturer) are now commonly printed on frangible stock with built in slices in it which breaks apart in 3, 4 or more pieces if you try to peel it off.
5 replies →
I guess they can use the cameras to show you were tampering with the labels and call the police. Somewhat related xkcd https://xkcd.com/1494/
Yeah, the prices the store chooses to display, not your own edits.
In which country?
spain