Aren't standards wonderful? There are so many to choose from.
Yesterday afternoon I wound up taking a few pictures with an unfamiliar digital camera. I forget the make, which is a bit unfortunate as it's probably one I best avoid. The digital cameras with which I am somewhat familiar, which are jmaynard's, have a certain shutter button behavior that I've gotten used to.
To take a picture with the cameras I'm used to using one presses the shutter button partway and the camera beeps or beep-beeps to let you know that it is taking or has taken measurements such as light level and range or focus adjustment. Then the button is pressed the rest of the way and the picture is taken, complete with the playing of an audible shutter sound to let you know you've taken the picture.
The camera I used yesterday was not set up like that. I'm not sure if it was configured different or designed different, but it was different enough to cause me trouble. When the shutter was pressed, there was a soft beep-beep and the picture was taken. I kept trying to push the button the rest of the way to take the picture and wondering why the camera wasn't working. I suspect that whoever owns that camera has two or three pictures of each shot I tried to take as I simply didn't believe the camera was working.
I suspect the opposite is what happened when wendyzski was using the camera I had at ACRF. I guess she heard the beep-beep when the button was pushed partway and figured a picture had been taken. But that camera was only getting itself set up to take the picture then.