I usually like to have the normal sound on though, in case someone calls/texts/IMs/etc. But I suppose that's an easier workaround than removing the file. That actually didn't work completely either (I now noticed), it seemed to silent it but it started again after a few days (and reboots). Not sure why.
I'm usually taking pictures of things like kids events, other people hanging out, etc and while I don't pretend I'm not taking pictures (it's very obvious I am) I take *lots*. Of the breed that wanted to be a photographer briefly in the early teens, I usually shoot 10-20 pictures per actually useful shot just kind of burst-mode or rapid clicking at whatever I'm trying to get. So while they know I'm taking a picture, they don't really know I'm taking 80 pictures. By then the sound would be annoying plus they'd paralyze and stop being good subjects to take pictures of (acting more or less naturally).