It can be a challenge, though, if someone has multiple allergies. I lived with a bloke for a while, about 20 years ago, whose son was an asthmatic, with eczema, and an allergy to eggs, so he couldn't eat dairy or acidic foods or egg-based foods. It meant no cheese, milk, yoghurt, tomatoes, citrus, or omelettes or other egg dishes, or foods using eggs like cake etc.
It was a major challenge trying to make dishes which were balanced, yet interesting, and I tried to cook one meal for all of us where possible rather than having to cook separate meals.
I think that putting signs near the food with a list of ingredients is good, but also I wouldn't try to limit every dish to beingallergy-free to every allergen, but make sure that there are various dishes available which allow for different allergies or food preferences. Pre-planning with others to make sure that at least one substantial dish is available for each need would mean that it doesn't all fall on your shoulders.
As an example, the succotash recipe above can be made without the bacon so it is vegetarian and it is egg-free as well. It wouldn't suit someone who doesn't eat acidic foods, though. The type of bread or accompaniment can be chosen from a range of alternatives, e.g. gluten free bread, or pasta or rice, or couscous, or whatever, So the dish itself is fairly simple, yet tasty, and can be modified in various ways if necessary but the individual with the allergy can choose the appropriate accompaniment to suit his/her needs.