I know in NY if you hire someone you have 90 days to submit his/her name to the state. I think it is everywhere now.. Part of the I-9 paperwork, but I may be confused.
Bottom line, you get another job when the first tax roll is submitted to the state you will be caught anyway. Many states troll the bank records, boat, house and other sizable assets looking for people who have more than they are admitting to.
For a few years, every October, my ex's state seized my bank account and took the funds (the magic number was more than $500.00). After the first year, I knew when it was coming and made sure never to have more than 2-300 in the account. They are allowed to do that under law, if they can do that, they can find where you work and how much you make.
for the comment about COL and short changing.. no where does it say the father HAS TO be the SOLE supporter.. that is so archaic these days. More realistically is the right to survive with some dignity and anyone who has been the courts knows what I mean.