Since your Chinese friends will always
                                    without fail beat you to the punch, since you are an honoured guest in China, here is what we sometimes do:
                                     
                                    Towards the end of the meal, go to
                                    the bathroom and on the way there just quietly pay the bill.  This usually works.
                                     
                                    This technique should only be used
                                    with Chinese at your own social level, or who are lower than you in Chinese etiquette - younger, employees - or students and
                                    friends at the same level.
                                     
                                    That is because you never want to
                                    cause embarrassment - or loss of face - to a Chinese who considers himself or herself at a higher social level!