Even so, ATMs are much safer than trusting the store clerk and whatever device they use to read your card. I know some magnetic stripe readers actually imitate

Even so, ATMs are much safer than trusting the store clerk and whatever device they use to read your card. I know some magnetic stripe readers actually imitates a keyboard and just "write" the card info. So if you gave focus to notepad.exe instead all the card info would be dumped in cleartext. "Oh, seems it didn't register, could you swipe your card again?"