I don't understand why someone would want to commit child support fraud. It's true that if someone doesn't have money, they can't pay child support. But if someone doesn't have money, they can't support themselves either.
Instead of trying such tactics, it would be much better for the parent to aim to make more money and to get better jobs, so that child support will not be a burden on them. He will have to pay more support with greater income, but if he is able to take care of his own needs without problems, I don't think child support will be such an issue.
There is also a moral side to this topic. Parents should not forget that the support they are withholding affects their own child. People may separate on bad terms, but what is the fault of the child? Raising a child is not easy and no parent should have to bear the costs on his or her own. I know that it's not easy and some parents do experience difficulties in order to pay child support. But this doesn't mean that people should break the law or become negligent of their duties as parents.