And we have NO idea what the actual employment status of the NCP is, except for what we're being told by the CP. He may be unemployed or being paid so little that he barely has enough to take care of himself. I don't agree with the statement that all who are CO'd to pay CS will pay even a little if they are unemployed. I don't see how, if they don't have ANY money coming in.
I'm sorry, but there are a lot of gaping holes in this situation. The first red flag for me was in the original post when the CP insinuated that their main objective was to get the NCP arrested. Yep, there is a tremendous amount of animosity, at least for the CP against the NCP. And that's the second red flag.
Regardless, unless the NCP is wealthy and obviously hiding money to avoid paying CS, there is absolutely no reason to put someone in jail for non-payment. Soc was adamantly against it, I remember, because he saw it as an equivalent to debtor's prison. It's the only way to guarantee there won't be any CS payments made, which defeats the purpose altogether.
As for law enforcement, you can't change the fact that a warrant has already been issued. But I would give them more credit in the fact that they don't want the child present if they arrest the guy anymore than anyone else does.