The taillight thing is almost always just a lil past locked. like on at 3 o'clock, off at 12 o'clock, parking lock at 9 o'clock, and a little farther past is parking lock w/ brake light at like 10 o'clock. Yea presumably to be seen at night if you've got to leave it on the roadside. Apparently it's a law that you have to have a parking light available even when the key is removed in some euro countries. modern bikes still have it, but not on the key switch anymore, usually just some series of holding down buttons to get the taillight to stay on.
Only thing i've ever used that "feature" for though was to be really pissed when I accidentally turned the key too far and didnt notice til the battery died. Still - worst case you bump start it and have dimmer than usual lights for 10 minutes?