No, not when that extremely important thing is a baby, and when you are the mom. That is, if you are a mom who has bonded to the baby.
Ever hear those surveys that claim that a man thinks about sex hundreds of times a day, or at least everry 5 minutes, or something like that?
Well, a properly bonded mom thinks about her baby about 1500 times a day, or every minute.
Only a mom who has an attachment problem with the baby could ever do such a thing as forget [!] about her child in the back seat.
(And granted, there are many things that can prevent a sufficient maternal attachment from forming, such as physical separation of the newborn in the hospital, or placing the infant in day care.)
I admit you may have a point. I'll ask my wife. If you look up "mother" in the dictionary, you'll see her picture.