A military facility being there isn't a secret to hide. There are lots of such places with a large board saying "no photograph".
You're just repeating what I said -
The planes are flying over at best a militarily sensitive area, not a top-secret site a la Area 51, otherwise the air space would've been closed to commercial traffic to begin with.
Everyone knows what is going on in that shipyard,
Not everyone flying on a passenger jet into/out of Shanghai is a military enthusiast.
Whatever MSS does isn't broadcasting something nobody knows.
Firstly, bit of a contradiction with your above statement ("
Everyone knows what is going on in that shipyard").
Secondly, you took the word 'broadcasting' a bit too literally -
Forcing the shades closed just clues people in as to what is up and risk a Streisand effect as everybody has now become curious.
What they does is to send a warning that they may take more serious and tough actions.
That's stating the obvious.
If we are being serious, then my suggestion was done as other member said and will be done when MSS gets serious. On the other hand, your suggestion doesn't work practically, for the safety for everyone on board, nobody is allowed to walk around during takeoff, climbing, landing and descent, sitting on his seat an air marshal would not see anybody doing anything next to their window.
Firstly, if we're seriously talking practicality, every passenger's luggage is already scanned prior to check-in and customs, all before even getting to the boarding stage. Flags would've been raised concerning anyone with the particular seating arrangement that would coincide with a view overlooking the shipyard along the flight path, and possessing the kind of equipment that could be identified as potentially engaging in "scenic photography" that would be easy for an air marshal onboard, who would likewise be seated accordingly, to monitor. And this is just one
speculation of how such a measure
may conceivably be implemented.
Secondly -
One solution - Posting air marshals on those flights to spot anyone trying to snap a shot during the flyover, then invite them for coffee as they disembark.
Emphasis on "
one solution", not the
only solution, let alone the best.