Missing argument x for notifications_anonymous_page_subscribe()

For some reason, I occasionally get requests to a site I manage at "/notifications/anonymous/subscribe/thread/nid", which is missing the last argument (the nid itself). These requests result in annoying errors from the site:

Missing argument 3 for notifications_anonymous_page_subscribe() in [path_to_drupal]/sites/all/modules/notifications/notifications_anonymous/notifications_anonymous.pages.inc on line 16.

To deal with this, I created a patch that sets a default value of null for the first three arguments to notifications_anonymous_page_subscribe(), then ensures that values for these parameters were actually set. Patch attached.