diff --git a/tests/test_core/test_authz.py b/tests/test_core/test_authz.py
index ce3889dc..541b1ee3 100644
--- a/tests/test_core/test_authz.py
+++ b/tests/test_core/test_authz.py
@@ -51,8 +51,12 @@ EXEMPT_ENDPOINTS = {'knowledgebase.track_click', 'users.update_user',
                     # docs/proposals/printedparts-plugin.md; justification in
                     # the plugin README.
                     'printedparts.kiosk_take',
-                    # Deliberately open kiosk writes, same bar as the parts
-                    # kiosk: they can ONLY move a USB device between
+                    # Deliberately open kiosk writes. NOT the same bar as the
+                    # parts kiosk, and the difference is the point: these are
+                    # additionally behind usb_kiosk_enabled, which the parts
+                    # kiosk has no equivalent of, so a site that never turns
+                    # them on serves 404s where printedparts serves a live
+                    # write. They can ONLY move a USB device between
                     # checked-out and checked-in, and only when a site has set
                     # usb_kiosk_enabled (off by default - every one of these is
                     # a 404 until then). Identity is a scanned badge resolved