I think there are other issues at play here too though in the sense that the assumption these days would be that all children are vaccinated according to the accepted schedules so it isn't something that a parent would likely think to ask about but might be concerned if they found out it wasn't what they thought. I would contact local daycare centres or schools and ask for their policy. If you contact your local health unit they will have the rules for your area but even within that there will be a caveat that children whose parents oppose on personal or religious reasons or a child's medical condition doesn't allow for vaccination - ex I had a dayare child with a severe egg allergy so she had very few that she could get. It isnt' so much deciding about what the other parents are comfortable with it is about you. It sounds like you are concerned for your own children and for that reason you have the right to decide that you will or will not accept an unvaccinated child into care. Yes making your policy now and then turning the new family away based on that rule is what you should be doing if that will make you feel more comfortable. It would be wrong to start them into care and then change the policy.