There is no geographic requirement, however, there are definitely quotas that must be fulfilled.Because they like the people they made offers to better, assuming they get cleared medically. There is no "fully qualified" status at CGA - they get to pick and choose who they want for whatever reason they want.
There is no geographic requirement for CGA, although they try to be representative.
When it comes to moving people around anything is possible and probably has happened at some point, but there is a separate waiting list for CGAS, so the chances of a kid on the appointment waitlist would be offered CGAS aren't likely, or they would be on the CGAS waitlist instead.
Are you talking racial or geographic?