There're clear reasons such as health or poor performance in practice but there may be some other causes to know. What would they be? Parents? Education first? Financial issues? What else? In the case that I have just experienced in a U10 and U12 competition in Chendu (China), it seems that the local coach does not like that kids get ranking points. He pulled out his 4 or so young players that were to participate in quarter-final matches of U10-U12 boys and girls saying to me that "to those tournament organizers it's just about the points". He personally apologized to me for my son was to play one of his tennis school's kids. His bitter apology appeared to have been directed at my boy 'cause my son was ranked number one while the other kid was way below. Watching his kids practice, I would see why he was worried (they all would probably loose). Well, my son ended up in the final which the Chendu kid would most likely not have a chance to get to. Anyhow, was this coach's reason to give up his tennis school's kids opportunities justifiable or not? Do the formal U10/U12 tennis tournaments in the US and elsewhere rank their kids? If so, what is the ranking system? And, how do coaches/parents of kids respond to the system there?