“It’s Montezuma’s Revenge.” Anyone mentioning the great Aztec ruler in this way usually has a nasty case of travelers’ diarrhea. The “curse of the ATM” is less well known. In Mexico, unlike in Switzerland, the machines rattle out your money first, and only then, very slowly and silently, return your card. I was already back in the hotel when I realized that my Maestro card was probably in the hands of strangers by now. What to do? Using the free WiFi in the hotel lobby, I instantly logged in to the UBS Mobile Banking App. One click and I was called by customer service who quickly cancelled my Maestro card. Credit cards and prepaid cards can be blocked directly from the app. I immediately transferred money to cover the last invoice for my MasterCard, which I had with me. The credit was available within a few minutes.