Well, I have to confess, sometimes I get a little confused. I was recharging some of my flash and camera batteries today and needed to move my camera bag to accommodate all the other bags to be worked with. So, after moving it around I was surprised (actually, quite surprised) to hear a constant “clunk – clunk – clunk – clunk …” sound of a rather ominous nature coming from somewhere behind the camera bag. At least, that’s what I though I heard. I listened, thinking it was some odd piece of household machinery I had forgotten about, buried deep in the wall, or perhaps in the bathroom on the other side of the wall.
Still the noise.
After a moment of punctuated slience, I realized it was my camera, making the muted thud of a shutter released inside the bag. I had left it on and when I shifted the bag the padding pressed one of the shutter release buttons. It had proceeded to dutifully take 30 frames or so of inky blackness 
The bag’s padding had muted the sound sufficiently to make it not really sound like what I’m familiar with since I’ve never actually taken pictures with the camera still in the bag…