If you can sneak a key into keyrings/live/pubring.gpg, and wait until someone runs blackbox_update_all_files without noticing, you then have access to all files

If you can sneak a key into keyrings/live/pubring.gpg, and wait until someone runs blackbox_update_all_files without noticing, you then have access to all files. Perhaps it should keep a signed copy of the last version of pubring and show a some kind of diff between the verified previous version and the current version before going ahead.