Should you be worried about credit card fraud when you pull up to the gas pump? A post circulating recently on social media says you can deploy your cell phone to stay safe.

An April 14, 2019, post on a Facebook page called “Local Jackson County News WV” told readers they can use their cell phones at gas stations to determine whether a pump has a credit card skimmer — a device that can steal credit card numbers.

The post said, “Just a tip, When you pull up to the gas pump to fill up your car, get your cell phone and search for Bluetooth devices. If a sequence of letters and numbers show up don’t pay at the pump. One of the pumps has a credit card skimmer inside of it. All of these skimmers run on Bluetooth.”

Can Bluetooth sensors always determine if there are credit card skimmers in gas pumps? We took a closer look.

How skimmers work

First, some basics: Credit card skimmers are real, and they’re illegal.

When installed in gas pumps, skimmers listen for the data traffic from the credit card reader, record it to memory and pass that data onto the pump controller.

Skimmer technology has become so advanced that thieves do not have to return to the pump to retrieve the stolen information. Perpetrators can simply sit in their cars and download credit card information to a laptop.

A special agent with the U.S. Secret Service told NBCNews last year that the agency recovers 20 to 30 skimmers a week, with an average skimmer holding information from 80 credit cards.

Can Bluetooth sensors stop skimmers?

Bluetooth can be a useful tool for consumers who want to protect their information, but they are far from foolproof.

Paige Anderson, the director of government relations with the National Association of Convenience Stores, a trade group representing gas stations and convenience stores, told PolitiFact that there are too many kinds of credit card skimmers to rely on a phone to detect them.

“Some use Bluetooth technology, some use cell service and some skimming devices store the data themselves,” Anderson said.

Vassil Roussev, a computer scientist and director of the University of New Orleans Cyber Center, said that a “hit” on Bluetooth “could very well be an indicator of compromise by a skimmer, but it could also be any number of other devices within 30 feet or so, such as devices in other cars. More importantly, not finding one does not mean the pump is safe.”

The skimmer need not be detectable by Bluetooth, he said, or it could be programmed to send signals only at certain times.

“Overall, I would say that this tip offers a low level of protection,” Roussev said.

Anderson added that checking for skimmers is something gas station owners and workers need to do on a daily basis.

Retailers should conduct daily internal and external checks and take other measures to foil data thieves, she said. These practices reduce the risk of potential credit card theft, she said, though they may not eliminate it.

Our ruling

Local Jackson County News WV published a post that said, “Just a tip, When you pull up to the gas pump to fill up your car, get your cell phone and search for Bluetooth devices. If a sequence of letters and numbers show up don’t pay at the pump. One of the pumps has a credit card skimmer inside of it. All of these skimmers run on Bluetooth.”

Checking a Bluetooth sensor in your cell phone before inserting your credit card in a gas pump may be able to determine whether the pump has been compromised. However, skimmer technologies vary, and many types of skimmers won’t be detectable using the Bluetooth method.

We rate the statement Half True.

This article was originally published by PolitiFact.