Not possible in the Age of Clinton. He made it so your paycheck gets garnished (regardless of whether or not you were faithful in your CS payments)
There's at least one case in TN where, so far as I know, the father takes odd jobs, gets paid cash, and doesn't pay.
A co-worker's ex works off the books in Pennsylvania (she lives in NJ) as a construction worker and the State of NJ is disinterested to pursuing him for back child support. He owes $80-85,000 for three girls.