I have a rule that if a parent shows up they must take the child with them - I explain it to them that it is a matter of trust between the parent and child. The mom promised when she dropped off the child to come back and pick them up so when she comes back she needs to keep her promise or the child will learn not to trust what she says. That in turn has negative consequences as far as the daycare goes. Often the parent asking about open door policy is asking because of negative info they have heard and I am honest and say when you arrive my door will be locked. Ring the bell and I will come as soon as I can but if I am tucking a child in or changing a diaper or pottying a child please be patient as I will assume it is a door to door salesman and not a parent in the middle of the day and not drop everything to rush to the door. I try to make it light and take some of the doom and gloom parents fear out of it. Then I go on to explain how the dropping in unannounced works and why and have never had a parent say they didn't agree. I also make it clear they drop in and must leave within 15 minutes because we have to go on with our schedule and it isn't fair to the other children whose parents can't drop everything and come. It rarely happens past the first month of care that they just drop in.