If you really want to be rude, go to a good restaurant and when you get your meal, take one bite. Then take your napkin, (hopefully it is cloth) and drape it over your plate and have the waitress give it to the chef. If the guy knows his stuff he will be completely insulted by what you just did.
I have had some bad food served to me, and I wished I had the courage to pull this maneuver.
Never heard of this use before - it is quite obvious (from your description) though.