Can someone please explain to me how rice, rice vinegar, salt, and sugar can contain gluten? That's all that is in sushi rice.
I can see how it might be a problem if you're one of the rare celiacs who reacts to distilled grain vinegars, as rice vinegar sometimes has grain vinegar in it, but for most celiacs sushi rice would be fine. I bet your waitress confused "gltuten" with "glutenous rice" which is another name for sushi rice. Of course sushi rice is gluten-free like all rices.
The sushi chef at the restaraunt where I am currently trying to eat () enlightened me to the fact that in many restaraunts, the rice vinegar added to the rice contains trace amounts of wheat to thicken it and make it more sticky. This may not be true of all rice vinegar, but you should always check with the chef where you are. Hope this helps (: