On the other hand, user may notice that suspend/hibernate does not happen from a laptop LED or hard disk activity without an audio alarm. Besides this is supposed to happen only in rare exception, so I think it is not worth adding any additional alarm. As for the implementation of xfpm_lock_screen, I think it is obsolete to use gnome-screensaver in it explicitly. I guess no distribution uses gnome-screensaver by default. Well, I could not find implementation of xfpm_lock_screen in GIT, so maybe this is not an issue anymore.
On the other hand, user may notice that suspend/hibernate does not happen from a laptop LED or hard disk activity without an audio alarm. Besides this is supposed to happen only in rare exception, so I think it is not worth adding any additional alarm. As for the implementation of xfpm_lock_screen, I think it is obsolete to use gnome-screensaver in it explicitly. I guess no distribution uses gnome-screensaver by default. Well, I could not find implementation of xfpm_lock_screen in GIT, so maybe this is not an issue anymore.