Sacramentans who have been supporting a surge in the number of sushi restaurants here the past few years well might be interested in this investigation by the Chicago Sun-Times. The newspaper visited 14 restaurants in the city, bought what was described as red snapper or "Japanese red snapper" and then had the takeout fish analyzed to verify that it was what the menu said it was. "Not a single one was really red snapper," reports the paper. Nine of the 14 samples actually were less expensive tilapia. There are laws meant to prevent this sort of misrepresentation, but as the investigation also makes clear, federal authorities responsible for enforcing them aren't exactly looking for such misrepresentation. Is this kind of misbranding occurring hereabouts? Though the Sun-Times probe was limited to the Chicago area, the report concludes that "there's ample reason to believe diners around the country similarly are being taken in."