Do you mean at your home daycare? Personally I do not see anything wrong with leaving an older child (like 4+) alone in a car for a few minutes while running into a house.

If they are leaving a child alone in the car and going through a parking lot into a building and down the hall...well I still am not convinced this is a huge deal but the law itself would likely have issue with it.

I do NOT EVER condone leaving a child of any age in a running car. This is a target for a quick car theft. Also, kids of any age should not be left in a position to drive off (it happens).

So ultimately it would depend on the age of the child and how long they are out of sight of the child.