This is your post. You asked for a single incident of a child being forgot somewhere, and the article link I posted had several, and said there were a confirmed 14 in a span of about 20 years of kids being forgotten in their car seats on roofs of cars. There are thousands of parents (that I can find with a fairly quick search) that admit to forgetting their children somewhere, at home, at an airport, at the store or restaurant, or even in the car, just they remembered before the child died. And not all of those 700+ children who died were forgotten. Some were intentionally left behind because the parent thought they wouldn't be that long. Some climbed in on their own. And then there's the guy who is believed to have left the child to die, but that is a whole other situation. The children in car seats on top of the car were likely there for less than five minutes, yet they were forgotten. Some of those parents had morning drives taking them 15, 30 minutes, or more, and they had to be at least concentrating on driving.
As I've said before, the reason we don't hear about the other incidents is because they are not nearly as likely to result in death, even if the child is left for hours.