[user104658]

I think I've said before on here, I've done it the other way before, when our youngest started nursery. She's always been quiet in the car, just sits peacefully so you don't really notice her... We had dropped the kids off at school / nursery then Awent for some shopping then driven home, and I got out the car then opened the back door to get the youngest out and had a moment of "Oh my god we've left her at the supermarket!!". Like a genuine horrible shock before remembering that she had started nursery and was there safe and sound.

I can understand how it happens the other way round. All it takes is a brief lapse of concentration in an exhausted parent, and they'll be sat at their desk at work fully believing that their child is safely in childcare. (As for people saying that "normal parents" call every half hour to check up on their kids in childcare... Err... No? That's not really normal? They have contact details for you if something is wrong.)

Again though it does need to be looked at to see if there's anything suspicious but with the assumption being that there won't be. Frankly (and morbidly) it ISN'T a particularly foolproof or devious murder plot, not in a car park that's actively being used, as again this actually happens a lot more than is reported - usually someone notices and raises the alarm and things end well.