I hear these types of stories all the time but 9 times out of 10 it is because someone is complaining about their situation and not actually taking action on it. If you have friends in this situation, it is either because they are in some back woods court that isn’t following the law, and I feel sorry for them, or they have screwed up orders that need to be changed and/or enforced but it suits them more to complain about how unfair the system is rather than do something. Or they are misrepresenting the facts of their case because it is a common occurrence for people to blame the system when the facts and the law do not agree with them.
I have also seen many situations where someone makes really good money but purposely hides it to avoid paying child support, but will show up with police like clockwork to enforce their visitation.
You should look for something else to validate your argument because you are in the wrong territory here. You said yourself that you haven’t experienced it and you are going by “stories” from people you know. I live this every day. I have gone through more divorces, custody battles, support battles than you can imagine and nothing is ever as black and white as you are trying to make it seem.