I've had a couple of customers ask me what flavorings I use in my cakes and when I mentioned almond, they asked me to leave it out because of nut allergies that someone has that was coming to the party. That got me to thinking, how many people even ask their customers if they know of any allergies in the family. I know that it is impossible to know who is coming and who has allergies, but I am considering not using almond flavoring because of it. I have some food allergies and know the consequenses.
I don't bake as a business, only as a hobby, but I am very careful about ingredients/allergies. I only use nut extracts in any of my baking when I know exactly who will be eating it. Otherwise, I leave it out. And even when I know that, when I give it to whomever I give it to, I am sure to mention/stress that it has X ingredients in it, in case they share it with anyone else. For cookies, I almost always individually package them with ingredient labels (and if I don't individually package them, I stick one ingredient label on whatever container they are in).
I have a severe nut allergy (specifically to almonds!) and always appreciate when someone makes sure foods don't contain nuts. On the other hand, if I am out somewhere it is my responsibility to make sure I know what I am eating. If I am unsure of the ingredients, I don't eat it! Bonniebakes, I think it is great you make sure the host/hostess knows what is in the cake. Most times I will ask if they know if the dessert contains any nut ingredients.