No one has properly thought this through at all beyond 'opening schools = getting people back to work'
Lets have a think. In secondary (Scotland) if we take back the exam years (S4, 4, 5) which are really the only ones who kinda need to go in - that's half the school. Current thinking is no more than 20% at a time.
Classrooms are generally small and packed. Current thinking is no more than 6 pupils to a classroom (to allow for 2m social distancing)
If the teacher has a class of 30.. that's 5 sessions of 6 kids to deliver ONE lesson. Who will clean between the classes coming in? what about corridors? Toilets? Canteen?
School lunch. Our canteen can hold roughly 1/3 of the school at a time if packed in like sardines. Do we start lunch at 10am and continue through til 3pm to allow for social distancing? Who will clean between groups of kids coming in? how long will that take?
If I am in school teaching one class over 5 periods of 6 pupils each - who will be delivering E-Learning to my other 5 classes that day?
Who will take the classes of the teachers who were here from overseas and went back home just before lockdown and now can't return without quarantine?
Who will take the classes of teachers who need to shield? Or isolate?
Who will take the classes of teachers who can't get childcare for their own young kids?
Your average school will have at least a third of staff who can't actually come to the building if it did open (for one reason or another).
If the solution is filling a marquee or assembly hall and giving a lecture style lesson to the masses - why on earth do they need to be in school for this when it could be recorded and delivered online?
Your average secondary is 800+ pupils and often much more. 70-100 teachers and staff. Narrow corridors, classroom changes once an hour with all 800+ kids switching room/desks/equipment. Its not an office of grownups where you can each sit at your desk/cubicle/workbench and not move all day. Its kids who will think it hilarious to cough in your face, to lick the door, to touch every desk as they come into and leave the classroom.
Even if every single one of those 800 kids live with a single parent and no siblings, that's 1600 potential 'sources' of infection. 1800 if you include staff. And each person will go home every night with whatever they picked up in school that day to spread it to home. A nasty sickness bug can wipe out a school and see it closed for a few days due to ill staff, and that's highly unlikely to kill anyone.
I have a friend who lives on one of the remote Scottish islands, Covid was brought there by 2 adults who had been on holiday to Italy. They came home on Friday. At the weekend their son attended an 18th birthday with such joys as 'dookin for apples' in a bath of cider and many 'drams' being shared around (one bottle, one shot glass, passed and refilled and passed and refilled).
On Monday they were not feeling so great, phoned NHS 24 and were advised Covid was v unlikely and to carry on as usual. Both adults went to work. On Tuesday night they were very ill and NHS 24 advised them to get tested. Both tested positive for Covid. Less than 2 weeks later the workmate of one of the adults was airlifted off the island by the RAF to intensive care and almost died. For the first two weeks there was extensive trace testing and every single positive result could be traced back to that couple, or their son at that party. Every single one. Infection rate was way above national average/per head of population. Then, the government stopped all testing there. It very quickly spread into care homes where no testing was carried out and throughout the community. Probably the strictest lock down in the UK eventually slowed the spread, but not before 7 people died.
It certainly shows how it only takes one infection source to spread like wildfire in a small, tight knit community.
Schools are incredibly hard to enforce social distancing in, a lot of people in a small confined space, to few toilets/sinks for appropriate hand washing, kids not known for their fabulous hygiene at the best of times and no way to properly clean rooms/equipment between classes. Even something as simple as door handles. Doors must remain shut in corridors as fire barriers. Very few schools have automatic doors (no money). There are 8 (!) doors between the main door and my classroom and that's by no means unusual.
I get why people want schools open, I really do. Teaching from home is a shit substitute, engagement is poor and many parents unsupportive. But at the moment, opening them is really not a great thing in terms of the spread of this virus.