the fact that it is bloody hard for one person to do does not mean that leaving children in the car is not risky. You can't say, oh, well, she can't do it therefore there is no danger. The danger exists, regardless. that is not a criticism of the parent. it is an objective assessment of the facts.
4 yr old twins, a 3 yr old, a baby and a school aged child, yes?
well, pushchair for the 3 yr old, baby in a sling, wrist straps for the twins and older child walking along side.
or double pushchair for the 3 yr old and baby, wrist straps for the twins and older child walking alongside
or baby in a sling, wriststraps for the 4 yr olds, reins for the 3 yr old and older child walking alongside
or double pushchair for the 3 yr old and the baby, 'buggyboards' for the twins and older child walking alongside
or a phonecall to the school asking for permission to park in school carpark or other staff carparking area.
- wrist straps are better than reins because they strap onto your wrist and theirs so you can still push the pushchair.