Anonymous officials

I really don't get how this stuff works.

So, I'm reading this article from Knight-Ridder reporters Ron Hutcheson and Drew Brown where they cite an "anonymous official" who is helping to give everybody an idea of how many National Guardsmen the President plans to deploy to "protect" the border:

A senior administration official, who insisted on anonymity to discuss the still-evolving White House plan, said that Bush would propose ways to plug security gaps until thousands of new border patrol agents can be hired and trained. The Senate bill calls for hiring 4,000 additional border patrol agents and 10,000 more immigration enforcement officers over the next five years.

The White House plan is to use National Guard troops, contract workers or local law enforcement officials in support jobs so that border patrol agents can focus on apprehending illegal immigrants.

The official disputed speculation that Bush would call for the deployment of 10,000 soldiers.

"The numbers are fluid right now. It will be in the thousands, but not that high," the official said. "There's a lot of different ways they can help without having to do the actual apprehension."

Then I find this in an article from Nedra Pickler discussing the big plans:

A White House official said Bush would propose using troops as a stopgap measure while the Border Patrol builds up its resources. The troops would play a supportive role to Border Patrol agents, who would maintain primary responsibility for physically guarding the border.

The official spoke on a condition of anonymity before the address Monday at 8 p.m. EST. The official would not say how many troops Bush wanted to use, except that it would be in the thousands but less than an estimate of as many as 10,000 being discussed at the Pentagon.

So, do these guys all and stand in a room with some "official," who tells them what to write, but won't let them identify him or her? Why? Obviously, this isn't some secret meeting at Starbucks—we're talking up to 3 reporters all getting the exact same story.
Or worse, is Pickler cribbing from the earlier KR story?