Can a school-age or under-age player play in a senior sevens team?

SA Rugby's Under-aged Rugby Regulations, Addendum 2 (Sevens) apply both the school age-banding rules and the adult under-age rules to sevens:

• School rugby: a player selected above their age band needs the coach to submit a Schedule A form to the provincial union, signed off by all responsible parties, before the player may take part. The front-row Schedule B clearance does not apply in sevens.
• Adult rugby: an under-aged player must be nominated by the provincial union and go through the clause 5 clearance process in SA Rugby's Under-aged Rugby Regulations for Adult Rugby. The extra front-row clauses (2 to 4) do not apply in sevens.
• The signed forms and official clearance must go with the player to every tournament or match. Without them, the player will be refused participation.

The front-row exemptions exist because sevens scrums are not treated like full 15-a-side scrum contests.