Originally Posted by
vanillabean
On another trip on another airline, a request was made before takeoff by staff to passengers overall not to eat peanuts, as one passenger was allergic to peanuts.
The peanut thread comes up every so often here, but you can probably glean more information from a google search. Basically, some peanut allergies are so severe that even airborne peanut essence can cause severe problems for the person with the allergy.