I do it regularly,includng the other day on fllght 14 SEA-EWR. They are happy to do it for you. Presumably one of the crew will have your regular meal, and, of course, it increases the choices for others. You do, however, have to ask for the rest of the setup (apppetizer, etc.) or you may not get it. It's fun to watch the looks on the faces of some of the other first class folks, who, if they'd known, probably would have done the same thing.
