My daughter has a really bad peanut allergy. School didn't want her to carry her epipen in her backback, or carry with her at lunch. We went into principal's office and told him that if she ingests peanuts, it could kill her, and that the minutes it would take to get the epipen from the school nurse were precious. He backed off, allows her to carry it with her at all times.
Her allergy is so bad that if I eat peanuts, and I give her a kiss on her cheek, you can see my lip prints on her cheek. Have we totally changed our diet? Well, I don't eat PB&J sandwiches any more. Do I get mad if some kid eats it next to her? No. But I tell my daughter to understand that she really has to watch what she eats. If my niece eats a PB&J and comes over to play, I make her wash her hands. I can't control what other kids do, I can only control what my kid is exposed to.
That being said, I hate all you fuckers that make peanut cookies and have your kids bring them into class to give out to your kids classmates. Heartless fucks.