Lock/unlock player

I’m so annoyed that this isn’t documented anywhere.  After two previous Clips, I bought the Sport.  Nowhere in the documentation does it say that it can be locked. I accidentally figured out how to do it.  Hold the BACK arrow down (the arrow at the top left of the controls), and it will lock!  I gave this unit a 1 star on Amazon because of the lack of a LOCK feature.  It seems I wasn’t the only one who was annoyed about not having one.  I would have thought that SanDisk would have chimed in to let us know.  Unlock, of course, by holding the same back arrow button down.  Sheesh.