If you think they are, just run out and try a back course with a VOR without a backcourse switch.
The reason an HSI reads "correctly" on a back course when set to the localizer heading is that the "arrow" is actually pointing towards where the localiser will be when you cross it, whereas in the case of a VOR, you are "from" a station that doesn't have a "from" side, and you are going "to" it so the needle has no option but to sense backwards.