I think they totally under estimate the logistics required to create these bubbles in secondary schools. Things like staggered lunch times even, our secondary school eat lunch in the atrium which is essentially the middle of the school. If this were in use pretty much all afternoon with different bubbles using it at different times, how would the rest of the bubbles move between classrooms without crossing this area.
School buses, how will they work with staggered start and finish times.
How will specialist teachers stay within bubbles, for example PE teachers, schools don’t have enough teachers in each subject to provide one for each bubble.
I genuinely think they are forgetting/ignoring the fact that secondary schools are run in a completely different way to primary!