In article , richard
wrote:

The USPS was owned by the US government but then a few decades ago it was
privatized.
Like any other private company, they can restrict photo shoots at any time
they so choose.
Is it illegal? Probably not. Those in power, or think they have the power,
like to show off their intelligence and authority by barking out "it's
illegal!". Even when it isn't.

If that happened to me I'd say, "Ok fine. Have your postal inspector arrest
me and charge me. You will then be able to explain to the judge precisely
why I was arrested and charged. What are you gonna do when he dismisses the
case?"

Sort of like "I'm allergic!" or "I'm calling my lawyer!" Occasionally
true, or appropriate, but mostly means "I don't like that" or "Stop
doing that."

In this case, and as previously stated, it's only illegal if they ask
you to stop, or leave, and you don't. Then it's trespassing. The
official policy is THIS, straight from the USPS::
----------------------
Still Photography

For Personal Use: Informal snapshots from handheld cameras for personal
use may be allowed at the discretion of the Postmaster so long as there
is no disruption to Postal Service� operations and provided the
pictures are taken from areas accessible to the public. In these cases,
no prior permission is required from the Office of Rights and
Permissions; however, no lighting or scaffolding may be set up, and
Postal Service employees, customers, cover of mail and security cameras
cannot be depicted in the pictures. Postmasters may restrict any and
all photography if they determine that it is disruptive or there are
potential security concerns.
----------------------
The key phrase there is "at the discretion of the Postmaster".
According to my girlfriend, who is a USPS supervisor, the default is
virtually always going to be "NO" unless you have prior permission. Who
knows why you're taking them, and there are "terrorists" in every
wastebasket. More seriously, postal facilities DO get robbed, though
they make every effort to keep it out of the media.