I can't see many people having a problem with this?
There will always be people who have a problem with anything that isn't 100% business as usual!
As someone has mentioned on another thread, there may be valid concerns for children who rely on lipreading, but I think they will be a small minority, and hopefully appropriate adjustments can be made for them at a local level.
There will be some children who genuinely can't wear masks, too, and there should be exemptions for them. However, I think there should be some sort of valid reason for exemptions, rather than just allowing people to declare themselves as exempt because they don't fancy it.