Food manufactures who use the "gulten-free" label can now only do so on products that have undetectable levels (less than 20 ppm) of gluten, and do not contain any ingredient containing wheat, rye, barley or their derivatives. Manufacturers who violate these regulation will be subject to regulatory actions from the US Food and Drug Administration. This ruling does not apply to restaurants.
PositiveTip: If you are one of the 3 million people in the U.S. with celiac disease, remain inquisitive and ask questions about your food.