It depends on each restaurant, however, in many cases they accept it willingly, because they do not have to contact the truffle hunter to have one delivered to the kitchen, but you will bring it directly to them the same evening. So always ask and in most cases they will be happy to grate it for you on the famous tajarin or some other good dish of the Piedmontese tradition. And if you don’t eat the whole truffle, they can give it back to you.