OK let's look at a real life scenario.

A mother of two small children (pre-toddler) needs to go shopping. She takes the kids out to the car, straps them into the child seats, hops into the front seat and is about to drive off when she realises she has forgotten to pick up her purse that is sitting on the kitchen table.

Question; Does she un-strap the kids, take them back into the house with her to collect the purse, come back out and strap them in again, or does she simply nip back into the house quickly and retrieve her purse, leaving the kids strapped in the car?

Answer honestly if you can.

So, she does her shopping, trailing the kids around the supermarket in a double trolley, packs all her groceries at the checkout, trundles back to the car, loads up the goods, straps the kids in and starts to drive home. Halfway home both kids are fast asleep, but she remembers that she needs a postage stamp and stops outside the post office on the way home to buy one. Now, does she wake both kids up (both will probably be quite fractious and tearful if she does) un-strap them, carry them both into the post office, buy one stamp, carry them both out, strap them back in again and continue her journey? Or does she make sure that they are soundly asleep, get out, secure the vehicle and pop into the post office to quickly buy a stamp?

This is the REAL world. What would she realistically do?