Perhaps it was to scare the pax to quite taking pictures because the FAM wanted to take a nap and did not want accidental documentation of his big breaking of the FAM rules?

Can airlinefood and FT co sponsor a photo contest? First person to produce a picture of a FAM eating a donut inflight wins.

As grahamb said "I've been on planes where they have said it is not allowed to take photos outside the plane (e.g. when flying into Vietnam IIRC) but that was always announced by the cabin crew and always referred to photos outside."

I figured certain governments have photo bans on military type equipment, but they made no announcements the time I was leaving Hanoi on Vietnam Airlines. I took a quick pic out the window from my window seat. The FA spotted me and came over, shook her finger "No Pictures". I nodded, put my camera away, that satisfied her and she left. For a moment there I thought I might find out what a genuine Communist SSSS was like.

They say the photo bans are to protect "military secrets". I think it is something else: preventing embarassment. HAN is a small airport, you can see everything there as you taxi out. I'd be embarassed, too, to let people take pics of the fact that the Military Might at the airbase guarding my capitol city consisted of ONE shabby looking MIG.