Last season's work is ideal, and pick the top of the job rather than a folder inside it. A convention's folder patterns are written from the top, so starting one level down reports every correctly placed file as misfiled.
Your files never leave this machine. They are read directly by your browser and nothing is uploaded; there is no account, no server, and no record of what you checked. Close the tab and nothing remains.
It is checked against its own manifest as well, for anything missing or damaged in transit. That needs no rule from you and no connection: the drive carries both.