She did catch a break; the other three or four times she left her daughter in the car unattended. We're not talking about a 9- or 10-year-old - a 2-year-old is still incredibly young and helpless in such a situation, whereas an older child likely would be able to free himself or herself from a warm vehicle.
I agree, if its true that she had done this multiple times before, then it is more than just forgetfulness.
What gets me, though, is that people do not think its possible for a good person to make a mistake that causes harm to a child. They think the parent who makes the mistake must be a bad person in some way.