Letter to "Dear Prudence" - Peanuts

I read Dear Prudence on Slate.com.  If you haven't your missing out on life. I am constantly amazed by Dear Prudence letters. (here)

But. today one got to me. It was about peanut allergies and this woman's friend... well I'll post part of it...

I am fairly allergic to peanuts. I’m not necessarily going to die if I eat one, but I will have an unpleasant visit to an urgent care center. I am cautious about my allergy and always mention my restrictions when eating out or dining at someone’s home. I have a friend, “Tina,” whom I love dearly, but she is a space cadet when it comes to details. As a result, she’s hosted two dinners in the last year that exposed me to peanuts, resulting in embarrassing (and panicked) exits for me. She was sincerely and profusely apologetic both times, and I forgave her oversights. 

Here is the thing to me... who puts peanuts in their dinners?  Twice?

I have never once made a dinner for friends, or even myself, and said, "Humm.. You know what this needs? Peanuts!"

Is there some giant peanut cooking guide I am missing somewhere? Is everyone cooking Thai food? WTF?