I can understand your fear. My son was allergic to eggs. While not deathly allergic, it still caused some significant health issues for us. And it was incredibly upsetting how many people violated his diet restrictions.
His preschool, which was fully aware of his allergies, gave him seven pieces of French toast one morning, and called me in a panic to ask if they should rush him to the hospital. (He was not exhibiting symptoms yet.) They also gave him EGG NOODLES a few days later because "they don't really have egg in them, do they?"
Never assume something will be obvious.
Never assume that others have common sense.
Our preschool posted a schedule of snacks and meals that were to be served each week, which I reviewed. I highlighted dangerous foods, and brought alternatives. Be warned though, they often make last minute changes to the schedule. (When they served him French Toast, that was a substitution for hot cereal that was made that morning, and I was never informed about it. A worker that came in late discovered my son eating it and called me.)
At the elementary school, he was given cakes and cookies a couple times a month. They "forgot." They also expressed to my husband on one occasion that they gave him cookies because "they know the poor kid doesn't get them at home." (Which wasn't true, by the way. I had egg-free recipes that I made for him, plus store brought brands that didn't have eggs.) Neighbors used to sneak him cake and cookies too, for the same reason. And they had been told of his allergies. It was very frustrating.
It helped when I would supply the school with safe alternatives for him. I'd give his teacher alternative snacks, not only for snack time, but also for birthday celebrations. Those were the biggest problems! Someone would bring in cake or cupcakes, and they would automatically distribute them to everyone!
Another irritation is that the school staff didn't know what contained egg. Mayonnaise, salad dressing, French toast, and any other food or condiment that isn't readily known for containing egg can be a huge problem. I gave lists of common foods that contain egg, and had them post it on the wall. Any time I saw a new staff member, I automatically reviewed the list with them.
I highly recommend you pack your own meals, and keep the staff constantly informed about the allergies, and provide them with stockpiles of snacks and such to give as alternatives.
It helped a lot when my son started to know which foods were acceptable and which were not. He often brought home cookies and treats he got at school, to double check with us before he ate them. Sometimes, however, the temptation for a birthday cake was too great, and he ate it anyway.
My advice to you would be to not trust that the diet will be followed. Whenever possible, provide your own food. And provide plenty of alternative snacks for the unexpected school celebrations. Never let the supply run out, and monitor the supply yourself to be sure it doesn't run low. Keep the school informed, and keep on them. Get tshirts and buttons that declare your child's nut and egg allergy:
http://www.zazzle.com/nut+free+gifts
http://shop.cafepress.com/allergy
http://www.zazzle.com/allergy+gifts
http://www.allergicchild.com/allergy_related_products.htm
http://foodallergies.about.com/od/livingwithfoodallergies...
http://www.miztees.com/a/allergy.htm
Be very wary around ALL holidays. Reward your daughter significantly for bringing you suspect snacks that are given to her.
Meet with the principal or other school official and ask for their assistance in protecting your child. They may have dealt with this before and might have good ideas for you. Find out who will be responsible for informing substitute teachers about your child's allergies. Check locally or online and see if there are support groups for parents of allergic kids, and look for ideas and support there.
Good luck!