Is It Acceptable To Suffer From Redundant Acronym Syndrome Syndrome?

On yesterday's Here & Now, host Jeremy Hobson talked about credit card fraud and said both "ATM machine" and "PIN number." Listeners took him to task for his redundant language, since the M in ATM already stands for "machine" and the N in PIN stands for "number."

Today, Hobson apologizes for his redundancy and turns to linguist Ben Zimmer to find out whether his verbal faux pas is linguistically acceptable. Turns out there's a term for it: RAS syndrome. It's short for "redundant acronym syndrome syndrome."