An article from The Washington Post about diner etiquette: "How to be a better diner".
Jarad Slipp, the general manager of CityZen in the Mandarin Oriental hotel, likes it when guests share as much information as possible when they're booking a reservation. If a member of the party uses a wheelchair, for instance, the staff will make sure he isn't dragged through the length of the dining room when he arrives. Allergic to gluten? Need a vegan menu? The kitchen is equipped to handle all manner of dietary requests from patrons. However, having such wishes noted ahead of time allows the staff to better "tailor the experience for you," Slipp says, and "make it even more special."
Restaurants want to hear from you about your dietary needs. So, let them know, ahead of time and watch as many restos will do their best to ensure your culinary safety and enjoyment.