So after doing a lot of swapping out my new 24-70mm II the other day when I was performing some lens testing, I can kind of see what the OP is talking about. When I was behind the camera (tripod mounted, not much room to stand in front of the camera) it was more difficult to mount than my original 24-70mm. Trying to grip and twist resulted in zooming if I wasn't careful.
Of course, I'm always VERY cautious when mounting a lens, and make sure I hear and feel the click of a secured lens.
I still don't see how someone could accidentally hit the lens release button once the lens is attached, but everyone holds their camera differently.