The shutter normally remains closed unless you are (a) actively taking a shot, (b) in "live view" mode, (c) in video mode, or (d) telling the camera you would like to manually clean the sensor (in which case it opens the shutter and deactivates the sensor.) I can't think of any other modes in which the shutter would remain open.
If the shutter is open when the camera is powered off, it will close the shutter.
If you look through the viewfinder and are able to see through the lens then the shutter is closed.
Tim Campbell
5D III, 5D IV, 60Da
