No Photography at the Pentagon Metro Station

There's a big sign that says No Photography now posted at the Pentagon metro station. I wonder if there are any teeth to this policy? In New York everybody gets in a tizzy about proposed subway photography bans that come and go, but in DC we're just posting mandates with no explanation.

In this case, I suspect they were posted by the long arm of the Pentagon. The same signs can also be found in the parking lot of the massive Pentagon complex.