If this helps, this quote is off the Australian Shccols Rugby Union website re eligibility
To be eligible for selection in an Australian Schoolboys Rugby Team a player must be–
- Under 18 on January 1 of the current year
- A full time student attending an Australian secondary school or its equivalent.
- Attend the Australian championships, if selected
- He must have been available for selection in all schoolboy representative regional or sub union teams, prior to or after the championships unless injured or under extraordinary circumstances—e.g. a family death.
- Noting – Attendance at Championships is not necessary for selection but they “shall be the principal guide.”
Its an interesting read especially for those players out injured and dont compete at the Championships but remain eligible for selection. Explains a lot about what happened last year.