There was one case I heard about in China where a truck driver hit a kid at night but didn't kill the child. To avoid having him self identified and fined, he backed the truck over the child again to finish the job just as the child mother ran outside to witness it.
From what I understand the driver got the death penalty. China has HEAVY penalties for running away from the scene of an accident and anyone ESPECIALLY FOREIGNERS are well advised to stay and face the music. If you show that you are trying to handle the responsibilities you'll be much better off than if you run like a jack-ass. If you run and they catch you, not only will you be royally screwed but you'll make it harder for other foreigners to independently explore China in the future.
CC