When managing a set a System Administrator will see a "Set Security Options" link at the top of the "Global Options" page. This link allows a System Administrator to grant or revoke read/write access to the set from any user.

Only a System Administrator can currently perform this function. Any user with System Administrator status will automatically see all the sets and does not require a specific set permission (granting a System Administrator read-only access does not overwrite their inherent System Administrator read-write access permission).