Originally Posted by craftymissbeth:
If they tell the ER it happened here are they going to report me? Am I going to get the bill? How in the world do people go about proving that sort of thing? I know without a doubt it did not happen here but ultimately it's my word against theirs, kwim? 
If it came down to your word against hers...
You are a professional, operating legally, have documentation of this accusation, contacted licensing prior to the mother, and other parents that are happy with the care you provide.
She has 2 out of control children and a story with a timeline that doesn't quite add up.