You can tell the directors, but I don’t know what they can do. Send out a notice to all parents? You may get a director that will speak to her personally and privately. Or they may do nothing, but it worth mentioning to them.
Not only is this a danger to the kids in the car, but to others around them. The area must have other children running about. What if one climbs in and puts the car in gear.
Being a mom and having to pick up older kids, I never left the younger ones in the car alone, not even for a minute. Yes it is a hassle to take them out and back in. But it is stupidity and laziness and huge lack of caring to leave a child alone in a car for any length of time.
Any police officer, paramedic, EMT will tell you how stupid this is to do.