Maybe being a bit thick here.. but surely a satellite will not be able to see if the doors are open or not as the doors are not facing the sky? (if I'm about to be called thick, in my defence can I just say been in the office for 12 hours so far today and feeling a bit tired)
First off, I was quoting Post #01 not making the statement myself.
But satellites do not need to be directly overhead, they can look in at an angle! however at first there were in fact inspectors from both sides who used to visit on the ground as it were.