From my sister: (an abridged version)
4 year olds can go to school, but university students who have paid for tuition they haven't had and accommodation they are not living in, can't go to university.
I can be at a school with many 4 year olds I am not related to and about whom I have no idea of their family's actions and interactions during the lock down, but cannot see one four year old I am related to and whose parents' actions I trust.
Youngest children go back to school first because..... they are notoriously good at not touching things they shouldn't touch, maintaining personal space at all times and have personal hygiene at the top of their list of thought processes.
I cannot sit in a park today or tomorrow, but from Wednesday that will be fine.
I can work all day with a colleague in a closed environment such as an office or factory, but cannot sit in their garden after work.
I should go out as little as possible, but can travel for exercise. So that's me off to Brighton next weekend, even though I live in the North West.