He is deathly allergic to mushrooms. In looking at menus for some of the places we'd like to eat, I notice many of the items that interest him (particularly steaks) come with some kind of mushroom glaze/sauce/topping, etc. How accomodating are the chefs to preparing meals differently for those with food allergies? I am sure for things like peanuts they are used to it, but mushrooms is not a common allergy.