It is like any system there are always a few who have less the pure motives most are just doing the best they can (think social welfare).
We don't have red shirting. You start school any time from the day you turn 5 (99.9% would start the first school day after their fifth birthday) until the day you turn six. You are put in a class according to your birthdate - if you start at six you get put in the classyou would have been in if you started at five unless there is a particular reason not to that the school agreed with. But our five year olds don't spend much time learning letters as they are supposed to be reading at level 12 to 14 after 12 months at school.
It seems to me if sports were organised by age not grade parents would not err on the side of caution so much. I do think still being at school at 19 is not a good thing.
