I have to say that let the market play out the rules. When people don't want to work overtime, they can leave the job to those who need to work overtime, and once those people who need to work overtime finally at a stage that he doesn't need to work overtime, the job will either increase its standard or go to another place where people need these jobs.
Actually, I think so. poverty is a problem should be solved, not child labour. If there is a place where children has to work, children has to work. They will need money to survive, or have something for their future generation. And yes, their lives are fked, not because there is not law for that, it is because of poverty. If all standards are the same across the globe, does developing world stand any chance of stealing those unwanted jobs and make their life better?
Many young people in China don't want to work overtime, and many do not work in factories, and many demand higher salary, that's how jobs are shifting to Vietnam, Africa and so on. Things will just work out.