Shoppers at a Walmart self-checkout were left puzzled after spotting red tape covering part of a card reader.
A Reddit user posted a photo of the machine, noting that the red tape was placed across the top of the card reader.
It was partially blocking the area where customers usually swipe to pay.
Walmart staff and regular shoppers pointed out that the tape itself wasn't mysterious, but its placement raised eyebrows.
The red tape in question is a commonly-used tamper-evident security seal meant to show if a machine has been tampered with. They are often used in areas known for card skimming crimes.
Reddit commenters claimed the tape had been incorrectly applied. 'That seal should be at the bottom next to the pin pad,' one user pointed out.
Card skimming happens when thieves secretly install devices inside card readers to steal debit or credit card information. That stolen data is often used for unauthorized purchases or identity theft.
'It's pretty common in higher-risk areas,' one Redditor wrote. 'I've seen the same seals on ATMs too.'
Multiple Reddit users were confused by red tap on a card reader at a Walmart self-checkout
Walmart locations, in particular, have become a recent target.
In one high-profile case, two suspects were caught after installing fake pin pads into self-checkout terminals at a store in Connecticut.
Police later issued an urgent warning for customers to double-check self-checkout machines before using them.
Officials also sent out a warning following a Sheetz self-checkout incident in Ohio.
Machines at gas stations have also been at risk of card skimmers, to which Reddit users claimed they've seen the same kind of seal.
'We have seals on the pumps in case someone tampers with it when we are closed. My location inspects it three times a day,' a commenter explained.
Security experts say shoppers should watch out for any pinhole cameras or loose-fitting card slots on machines -- two common signs of skimming devices. Keypad overlays that log keystrokes are also frequently used by scammers.
Some people, like TikTok user FLM FLIGHT, have even taken to social media to show how they inspect gas pumps by tugging on the card slot to make sure it's firmly attached.
A Reddit user claimed Walmart customers have frequently fallen victim to card skimming
The social media users tugged on both sides of his car after placing it in the card slot attached to the pump.
In general, a solid card slot is a good sign. A loose or unusual one could indicate criminal tampering.
Other banking experts claimed loose and solid slots on gas pumps are a good way to tell if a criminal installed unusual devices.
Card skimming scams are estimated to cost consumers and banks about $1 billion each year.
If you suspect your card has been skimmed, it's important to report it right away, cancel the card, and request a replacement.
Experts also recommend changing your PIN and staying vigilant with all your accounts.