Any one who thinks it couldn't happen to them is delusioned.
DH made it to the works carpark with one of ours. Like everyone else it was change of routine, I normally did drop-off, can't remember what I was doing, ill or dentist or something but DH clocked LO before he left the car.
It does make you wonder how often does it happen but the kids are OK, uncomfortable but OK. We only ever hear about the tragic cases that make the international news. But that must be the tip of the iceberg there must be loads more who get left and are remembered before tragedy strikes.
One thing the UK does do is have nurseries make contact if a child doesn't turn up maybe that should happen everywhere.
I've also laughed at an ex-neighbour doing a 3 point turn outside their old house, having moved a few weeks earlier. Obviously driven 'home' on autopilot.
I also know a 'new mum' who left the baby outside the butchers, baby is 50+ and survived.
People definitely go into autopilot doing the same thing every day.