Quote Originally Posted by photomc
Good point Dave..he was a postal employee. Asking just because in this post 9-11 era nothing is for certain anymore. Admit it irritated me to know end, but I know some buildings are off-limits, but this did not seem quite right..more like something that someone thinks is fact, but isn't.
If you were not on government property, he can't tell you to do anything. Even if you were on USPS (which is only quasi-governmental, BTW) property I would question his jurisdiction unless he's part of the Federal Protective Service, which provides security for Federal Buildings.

I work at a US Government facility. If we observe a breach of security we call the FPS. I'm a contractor, but not even the Fed employees can take any action on their own. Unless I'm challenged by a uniformed officer with a badge, I'm very uncooperative.

I would've continued photographing and told the man to kindly bugger off.