I can't believe this! My pick-up time is not negotiable. I am very clear on this during the interview process. I have obligations with my family outside of my work day and that is not something I am willing to compromise. My contract states that I charge a late fee of $20 per 5 minutes and that late pick-up is grounds for termination.
I understand that once in a while there may be an incident that is truly out of the parents hands (ie. a snow storm or traffic), but personally I know that I would feel very resentful if I had parents disrespect me and my family (not to mention their child) like this. I wouldn't be able to get over it and would terminate care with them.