It wasn't antifreeze...or all the kids would probably be dead. It was windshield washer fluid, which is basically alcohol and soap, although it's the bad kind of alcohol.
Lots of people serve children fake fruit juices (I call them "bug juice"...because they attract bugs on a hot summer day) and they buy them in huge containers at warehouse club stores. I can see how someone could buy a gallon of bug juice and a gallon of washer fluid at the same store and accidently mix them up. Accidents happen. I'm just glad this woman did the right thing and called for medical assistance for these kids and didn't just try to hide what she did. That's commendable, I think. I don't think she should necessarily lose her babysitting license for this incident.