@Whatelsecouldibecalled should another barrier be put into place to prevent effective learning?
Learning isn't more important than someone's life.
You're saying children don't pass this to each other, but there won't be evidence of this from when schools have been closed and they've been at home mixing only with their households for months! There will be if they go back with no distancing or masks!
Most youngsters will not comply with bubbles on the bus and mask wearing or social distancing so not sure how wearing a mask in a lesson will help
All the more reason to stop them spreading what they catch elsewhere to everyone else unfortunate enough to share the classroom with them, including their teacher.