In the early 2010s, hundreds of Belgian customers discovered that their ATM cards had been cloned, resulting in the theft of 600,000 euros before the fraud was uncovered. The fraud was not detected by bank alerts or concerned customers, but due to a mistake made by the criminals themselves. A skimmer — a small device placed on an ATM — allowed the copying of card information and the withdrawal of money without detection for months. The device, which looked normal, included a card reader added to the original slot and a mini-camera or fake keyboard to capture PINs. Customers withdrew money without realizing their cards had been duplicated. The fraud went unnoticed by banks’ usual monitoring systems, as the withdrawals appeared normal and the cloned cards worked like genuine ones. The scheme collapsed when a suspicious deposit into a regular bank account was flagged by anti-money laundering systems. This error in handling the stolen money led to the discovery of the fraud. The investigation traced the responsible network back to the financial link, which broke before the technical link. In response to this incident, twenty-three Belgian banks decided in January 2011 to block by default the use of the Maestro card outside Europe, rather than implementing a general anti-skimming protection system. This measure significantly reduced cases of fraud. At the time, authorities ruled out the idea of a universal anti-skimming security for all ATMs, estimating that such technology could be bypassed and might lead to fraud shifting to less monitored terminals. More than fifteen years after the Belgian case, skimming remains a persistent threat. A complete device, including a cloned card reader and a micro-camera, still costs criminals between 7,000 and 10,000 euros, with potential theft reaching several hundred thousand euros. A more recent case in Vitry-sur-Seine in June 2025 involved fraudulent withdrawals from Spain, leading to the seizure of about 9,000 euros by French authorities. The miniaturization of electronic components has made these devices harder to detect visually. Current recommendations emphasize simple but effective actions, such as checking the ATM slot before inserting a card or enabling real-time banking notifications to spot suspicious transactions. The 2011 Belgian case shows that banking security depends not only on preventing theft at the moment of withdrawal but also on detecting unusual money flows. The skimmer could have remained active much longer without the final mistake made by its operators. This case remains a striking reminder that human error can expose even the most sophisticated financial crimes.