Although it’s the Chinese tradition that require children to fulfill their families’ need, to piety their parents, I don’t think restaurant owners should make their children working without pay.
I don’t believe one more paycheck (to one more part-time worker) will bring down the business.
I think children should make use of their own time to explore their endless possibilities. He/she could be a diplomat some day, if he/she hang out with his friends more; He/she could be a excellent scholar, if he/she spend more time in the public library.
Chances like this should not be taken no matter what parents do for living.
Or you may say as someone would: Hey Tim, your world is too perfect.