One sibling very sick..other one still comes?

[mom-in-alberta]

I think you did exactly the right thing, and I hope she didn't give you grief for it (especially if you weren't even calling her away from work!!!).
It's tough with siblings, because as playfelt said, it's possible that they won't both get sick. If it was me as a parent I would probably keep them both home. But as a provider, all you can do is look for the symptoms to arise in the second child. You can't ask them to keep thier child home because they MIGHT get sick.