Proms is a mainly American thing Jay, not something common over here although there are a few establishments that are starting to follow the practice.
The stages for schooling over here, they start in the infants, when they are 7 it's the juniors, when they are 11 they move into either secondary or comprehensive until 16 when they can leave or go onto higher learning either upper 6th form until 18 then move to either college or university depending on how clever you are.
When I was at school in the 40s/50s the leaving age was 15 and as far as my parents were concerned I had to leave then and start to earn my keep.
I've not looked at the link yet.
Just looked at the link, I see they picked the place I grew up.
It's true they should have put the ban in place straight away instead of giving them until Monday, I've heard it on the news that it means large groups of people are using the weekend to get together before the restrictions come in which is just going to make matters worse.
The goverment are to blame a lot for it, their own members flouted the rules and weren't punished so a vast amount of the population thought if they can get away with it why can't we. They were too slow at the beginning as well putting restriction in place.
And that is the last I'm going to comment on the matter I'm not getting into any political arguments/discussions, whatever you want to call it.