How to mute the camera shutter sound effect? It used to be that I was able to use the lock switch on my iPhone to mute all alerts and sounds (with the exception of any music, video, etc.); and this included the camera's shutter noise. Then when I went to set the switch to the un-mute setting, I could get the camera's shutter noise back.

This was especially useful when I needed to inconspicuously take photographs.

It seems now, though—perhaps even as early as iOS 5.1, I can't recall—the camera noise goes off each time I take a photo, regardless of other mute settings.

And I've already toggling the Settings » Change with Buttons setting, it has no effect.

Is there some sort of hidden option I've lost track of to let me regain this functionality?
Some countries (notably Japan and South Korea) have laws requiring camera phones to make audible shutter sounds.  

I can't find a definitive reference for this (at least not one in English), but there are many second-hand references if you Google.