I haven't read all of the replies but I will answer your questions.

I am in NS. Here, Public Health have guidelines for the situations when a child should be excluded from the day care. Fever, vomiting, diarrhoea are automatically a full 24 hour exclusion.

This is in my contracts and I expect full co-operating with this and the rest of my sickness policy. I do understand that getting a sick note is a inconvenience. I do also understand that having time off work when your child seems better after less that 24 hours is an inconvenience BUT...Bringing a sick child into my home, exposes my family, my other day care children and myself to the illness. It's an inconvenience when your child infects other children and their parents also need time off. It's an inconvenience to everyone if I get sick and have to close.

This is in my contacts however, and clients know this when they come here - and I will and do enforce it for the reasons given.

However, from your post, it seems this is a sudden, middle of the night policy change. In terms of the contract you have with your provider, neither party can simply change the contract, effectively immediately without both sides agreeing. If your contact has similar exclusions to mine, then you signed it and legally you have to abide by it. If it's not in the contract, then unless Public Health in your area has these guidelines, then I'm not sure the change can be enforced.

I do agree that the 3am phone call from the husband is highly unprofessional. There were better ways of handling that but as you said, tired frustrated parents sometimes don't make the wisest choices.

What does your contract say?