As a white Canadian who lived in China for five years, I have been on tours with Chinese tour groups (with my Chinese wife) and foreign tours. A tour guide on a Chinese tour wouldn't dream of asking for a tip...he not only wouldn't get one, he/she would lose face. Unfortunately, some Chinese tour guides operating tours with foreigners have learned of the strange western custom of tipping and will take every opportunity to not only ask for a tip but demand it. They will even do this on tours consisting of Chinese from foreign countries. They would never try this with Mainlanders.
Brian
Just a further word on Tipping in China

Brian-C2
June 17, 2013