Forget exactly why you were terming them but sometimes parents do learn their lesson. Now that they have been in "time out" - sent away from the daycare to think about their behaviour, they just might become your best most conscientious set of parents. This of course assumes the parents were at fault and not the child.

I have taken a family back that had a tantrum and left care only to find out I was right and it was the same rules at other home daycares and the grass wasn't greener on the other side as they say. Strict rules for the return, a long talk about what the problem was, about communication and about how it was my house, my rules, my right to let them go again if they didn't follow. Second time around it worked out well and they returned after the birth of their second child too. She is still on my list of references I give out as a past parent and her child has been gone now since 2009.