We see the awareness of allergens within the food world growing. The comparison of 20 years ago would be that you might get a severe allergen request once a month, now, multiple times a day. Children today have a 500%(exaggeration) greater chance of developing an allergen that could affect their life in a multitude of crazy ways. Children at the end of the last millennium did not have, understand, see, believe, or accept the fact that there is an issue with your body due to something in your immediate area.
There are many theories out there from government conspiracy experiments to gene degradation of why we are where we are today as a world. I feel that it is a combination of all the theories. If you take the last 75 years of the culinary world and the innovations created, designed, and mass produced by the worlds' war machines, rapid cultural expansion due to air travel and the blending of the atmosphere's stew of turmoil. You can then begin to construct the labyrinth of iconic foods that curved our relationship away from nature and into a laboratory.
I have seen a large increase of the percent of people affected by an allergen. An even greater increase in the severe allergens has been noticed in the last 5 years. It is my belief that through modern medicine and alternatives to natural ingredients has drastically changed how our bodies identify potentially harmful molecules. Building up tolerances to antagonists was the way of Darwin. The simple thought of survival of the fittest doesn't always apply to the world anymore. With the life saving power of medicine and technology its anyone's game.
The approach I take with diners is you have the allergen not me. I can prepare food that will not kill you. You just have to ensure you completely understand your restrictions. I have the empathy and compassion to help those in need and any chef who refuses to TRY to accommodate an allergen should stop cooking. Sometimes the time crunch or circumstances don't allow for total inclusion for those with allergens. The diners with allergens have to remember NOT to put the responsibility upon the Chef, but upon themselves.