My dad spends his days with children whose parents don't buckle them in car seats - the trauma center. He spent his shift not to long ago helping another nurse clean up brain matter that had leaked out of a little girls nose because mom and dad decided not to put her in a seat. The force of the impact was so bad that her brained swelled to the point of having no place else to go but out her nose when she coughed.
While it may not be "child abuse" it's an exceptionally stupid thing to do today. I'd certainly rather spend a couple of minutes buckling up my kids - than a lifetime in that mother shoes.