As he's been reporting for NPR.org in recent months, Alan Greenblatt has noticed something unusual: he's increasingly being asked to prove who he is and that he is, in fact, a journalist. Here's what he found when he started to ask why that's happening:

How many people would bother to impersonate a reporter? Enough, apparently, to cause some government officials to do preliminary background checks on people to whom they grant interviews.

The other day, I arranged to speak with Bob Wirch, a Democratic state senator in Wisconsin. The morning of our appointment, I received a call from one of his aides, instructing me to bring along a press badge or some other credential that included a picture and identified me as a reporter.

This rarely happens. In some 20 years of interviews, less than a handful of people have ever asked me to prove that I was the reporter I was claiming to be.

But, increasingly, elected officials and their staffs are checking journalistic bona fides, going online to read old stories and check out photos. Wirch's aide actually congratulated me for managing to keep my own image off the Web, but said that was the reason she needed identification to be sure I was, in fact, Alan Greenblatt.

You'd think, of course, that if I were trying to impersonate someone I might have gone a different direction: Bob Woodward, Carl Kasell or maybe Ron Burgundy.

The folks in Wirch's office aren't the only ones checking out reporters.

"We don't let anyone in that we're not familiar with," says Darren Pudgil, press secretary for San Diego Mayor Jerry Sanders (R), "and, yes, we're very good about checking press credentials."

Pudgil says there are security concerns involved, as well as the worry that someone who identifies him or herself as a blogger or tweeter might turn out to be an activist with an agenda who will show up at a news conference with the intention of embarrassing his boss.

"We're very open and we're very transparent, but we're very thorough in checking out who we let have access to the mayor," Pudgil says.

As newspapers and other news outlets have scaled back their coverage of state and local governments in recent years, it's also led to growth in the number of citizen journalists trying to take their places.

"Since 2008, there has been an influx of bloggers or social journalists who have filled the seats of traditional journalists," says Meagan Dorsch, public affairs director at the National Conference of State Legislatures. "In some cases, the bloggers are the only people reporting from the statehouses, with the exception of the Associated Press, which I believe is still in every state."

So there are a lot of new and unfamiliar faces. That's another reason why, although it's still highly unusual for government offices or organizations to insist on seeing press credentials, the practice is likely to become more common, according to Edward Wasserman, who teaches journalism ethics at Washington and Lee University in Lexington, Va.

"There's probably a certain amount of apprehension on the part of sources in terms of what they're getting in for," Wasserman says. "It strikes me as a little belated recognition that there's a lot of fraud going on and there's serious downside risk, if people are not careful."

In the movie Borat, Sacha Baron Cohen did pretend to be a Kazakh journalist. "There are a lot of, quote unquote, documentary filmmakers out here," Pudgil says. "We don't let them in with the mayor. There's not much good that comes out of that."

But a lot of what Wasserman describes as "fraud" involves reporters or other media types presenting themselves as something other than journalists — James O'Keefe videotaping ACORN employees offering housing advice to a woman pretending to be a prostitute, for instance, or his assigning other Project Veritas employees to pose as big-money Arab donors at a lunch where they solicited embarrassing comments from an NPR executive.

The concern Wirch's office had in Wisconsin sprang out of an incident last year, when Scott Walker, the state's Republican governor, took a prank call from a New York blogger pretending to be David Koch, an oil billionaire and one of Walker's leading financial backers.

In other words, the real risk is not that people will pretend to be reporters. After all, when people talk to reporters, they are generally on their guard and certainly should be aware that their words can be transmitted.

And if someone comes knocking at your door under the guise of being a journalist, all you have to do is make sure what you say is fit for public consumption.

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