Interesting comment over on the UA forum about a FAM ordering a PAX to not take pics. Is this an actual law?

http://www.flyertalk.com/forum/showthread.php?t=544568

Here's the relevant part of the post:

Surprising occurence on this flight was I was up taking pictures outside of the Rockies, the seats, my wife, etc. when a FAM caught me from behind, pulled me to the front galley and forcefully told me I couldn't take pictures inside the airplane. I just told him I would show him the pictures and he could erase whatever he thought was inappropriate, but this was all outside the window and of where we were sitting, not the flight deck door or anything like that. After he sat back down and fell back asleep (completely serious) the FAs apologized to me and wanted to figure out what was happening...they were just as surprised as I was.

Next Monday Mrs. GRE and I will be in the UD for the first time ever. Of course I want a pic.