Whem my kids were little, I was always afraid of this happening, though granted, I never forgot them in the car. But the fear was there.

I also had recurring nighmares about driving in the car off the ledge or something into the water, drowning and having to decide which one of them to save first. I remember waking up in cold sweat every time I had that dream. Oddly, it stopped after I told someone about it. It's like saying to someone else made me realized how insane and unlikely it was.