I'd be very tempted to ring the school/daycare. Seems a bit petty to say "oh I saw on fb these kids are sick", but at the same time if she thinks they shouldn't be there but sent them anyway, that's really poor form.

Dt a kinder of 700 - wow! That's amazing. Do you live in Australia? Great idea to do fever checks though. Do you feel like the policies actually result in less sickness?