Yes they still try to collect in any way they can. If you don't pay it then it goes to owed child support. They don't care if you don't have a job. Also they can put a lien on all your personal property.
The non-custodial parent will still owe child support, even if he or she is disabled and on welfare. However, most states will not garnish needs-based assistance such as disability or welfare payments. So if the parent is not working and does not pay his or her court-ordered child support, it would be difficult for the state to collect. He or she might still be arrested and jailed for failure to pay.
No, but that's not possible unless approved by both the other parent AND the court, provided the other parent is not now, nor in the future, collect Welfare.
"reimbursed" ... Not clear whether you mean collects welfare or collects child support, but in either case the answer is, the State will not reimburse the NCP.
It depends on the state you live in. Some states allow the custodial parent to opt out of child support. Other states don't give you that option, and will collect the child support even if the custodial parent refuses to accept it.
Welfare
If the custodial parent is on any public assistance he or she must attempt to collect financial support from the non custodial parent or they will be disqualified for public aid.
First, it is an Urban Myth that fathers go for custody to avoid paying child support. First, who would support the children while in his custody? Less then 15% of mothers are ordered to pay, and depending on circumstances, the custodial father is often still ordered to pay child support.
you should be the one receiving it
Your custodial parent can collect unpaid support that accrued under an order. Support sometimes continues after the child becomes an adult if the child is disabled.
Child Support Enforcement will an interstate action under the UIFSA.
A parent who is receiving public assistance (including SSI) should not be ordered to pay support.
Most states do not allow a child to collect back support as an adult. Although the right to child support belongs to the child, support is payable to the custodial parent to assist in the care and upbringing of that child. If the custodial parent did not receive that support, then she (or he) made contributions that should have come from the other parent, and the right to collect the back support belongs to her.