L.P.
The airline can't and won't guarantee a peanut-free flight. They can't control what each individual passenger may bring or have packed with nuts on a flight. You can only do your part like you said by wiping down 'your area' of the plane. We have already flown twice this summer and on both they still offered snack items (for purchase) that have peanuts/nut items in them. Peanut M&M's for one and a snack mix with nuts, sunflower seeds, seasame sticks, dried fruits. Also if you take a DVD player consider headphones if you haven't already. If you have the volume up and someone else on the plane is annoyed by it, they will ask you to use headphones or turn it off. That happened recently on one of the flights I took and they had to turn it off because of no headphones.