Hmmm...who says she didnt think of her child? My supposition is she thought the child was safe at day care...yet, was not.
This isnt the first instance of a child being left in the back of a car.
If you play out the lack of sleep, quiet child, morning rush, preoccupation, and subconscious feeling of routine scenario...it's not implausible.
I doubt this woman is heartless...and, for her...odds are her life is ruined.
I doubt she's a monster too, however, I think this type of horrifying incident points to one of the problems with daycare. It occurred to no one to question the whereabouts of a 5-month old for an entire day. If no one sees that as a problem, our society is completely screwed.
I'd like to think at a bare minimum that a daycare/ school would call all available numbers if a child did not show up when expected. And I also think it's terribly sad that any mom or dad would need a phone call from a stranger to remind them about their baby, but I realize that is reality for some.