I have a behaviour management policy as part of my contract. It is given to the parents and posted at my daycare entrance. I don't know if you have this kind of policy with your parents, but it would be a good idea to start using it. Then there should be no surprises or guessing what to do as it has been already agreed upon.
Part of my policy states:
If the action/behaviour continues even though the child care provider has tried the previously stated methods of discipline (I lay out for the parents what I do - redirection, time-outs, etc), the child care provider will discuss the issue with the parent/guardian to seek their support.
If the action/behaviour persists the parent/guardian may be asked to withdraw the child from the child care home.
Any abusive, violent or aggressive behaviour that endangers the child, other children, the child care provider, equipment or building will not be tolerated. After the first offense, the family will be notified immediately. In extreme cases (physical violence and/or hitting) OR after the 2nd offense, the child will be suspended for 3 days. In the event of the 3rd occurance, the child will be suspended permanently without prior warning being given.