I got the impression she had the boys in the car as she drove to work (which happens to be a daycare). Instead of taking them inside with her (?!), she left them in the car. Her story seems to be that she thought her husband was going to show up shortly thereafter, retrieve the boys from the car, and take them with him.
In other words, she claims she was using the car (and car seats?) as a temporary holding cell for the two little boys, ages 3 and 5.
Whatever her excuse is - it cannot satisfy the reason for leaving children in a car - hot or not!!