yeah makes for an interesting ethical argument. For my two bob's worth if you've been deemed to have lost the privledge of parental responsibility it is because a court has determined it is not in the best interest of the kids to spend time with that parent. That is due to poor choices by that parent. Doesn't negate the fact that kids cost $ and it isn't the kid's fault that one of their parents is a twit...
That said, I agree with you. Not worth the stress, especially if the other parent has the capacity and desire to hide income from CSA