Cards Trapped Between Phone and Wireless Charger: It Is Rarely the Bank Card That Dies
A bank card's black stripe needs roughly 4,000 gauss to wipe, while the magnets in a typical magnetic accessory measure only 50 to 200 gauss at the surface. The fragile ones are hotel keys, access badges and older transit cards, and the culprit is not the magnet but the alternating field during charging. Here is what the bench tests and Apple's own documentation say, plus a practical checklist.