I don't mean to sound like a jerk, but is this really necessary?
I understand some people have an allergic reaction to peanuts. However, where does Delta draw the line with inconveniencing an entire aircraft full of people because of one person? I am allergic to cats, does that mean that no one should be allowed to travel with cats in the cabin on any flight I'm on? I know cats v. peanuts isn't exactly the same, but I think the point is still valid.
Also, there have been many studies done, most recently by a Harvard pediatrician that say unless the allergic person actually eats the peanut product, the risk of any kind of reaction is little, and the risk of a serious reaction is pretty much nil. Just being around peanuts will not cause a person to have a major reaction, that is an exaggerated belief and has been discredited through studies. Even if the person was worried about inhaling peanut dust, they could wear a surgical mask to filter out any dust in the air.
I always go for pretzels, so I really don't care. But situations like this really call on the individual to take personal responsibility (wear a mask, long clothes if concerned about oil) rather then relying on someone else to do it. I know most on here will say "it's just peanuts, who cares?" I really don't, but where do we draw the line?