I have never heard of this but next week one of dc will miss a whole day of lessons to spend the day couriering messages from the office and the classrooms, apparently they take it in turns. I have never heard of this! We used to cover reception at lunch if they were short staffed but not the whole day.
I'm guessing it will be good experience for them i am just suprised as the school is very very strict to the point one of mine wasnt allowed on a group trip with their class because they had been on a school residential over the weekend missing one morning of school the week before and it was vital they didn't miss a full days lessons as it would have a massive detriment 