A little paranoia never hurt anyone, especially when using the card.
While in Vienna on vacation, the security expert Benjamin Tedesco discovered a card skimmer, that is, a facility that steals data from tourists' cards.
The device could very easily be mistaken for the original ATM slot, being a perfect replica glued over the original piece.
Moral: pull the ATM a little before you put your card in it.
Via TechCrunch.