A fib by Veterans Affairs Secretary Robert McDonald about serving in the Special Forces shows just how big the problem military men and women call "stolen valor" is, according to a South Carolina man who has made it his mission to root out people who exaggerate or even fabricate their service.

As bogus boasts go, the claim McDonald -- who graduated from West Point, completed Army Ranger training and served in the vaunted 82nd Airborne Division -- made to a homeless veteran in an exchange caught on video last month was relatively mild. But given his job title and responsibility to see to the welfare of America's veterans, it stands out, said former U.S. Army Sgt. Anthony Anderson, who investigates incidents of stolen valor and maintains the website GuardianofValor.com

“His position is one in which he needs a lot of integrity,” Anderson told FoxNews.com. “McDonald claims he spoke incorrectly. I don’t see how he could have.

“It’s enraged a lot of people,” Anderson added. “It’s an integrity issue. Once your integrity is questioned, it’s hard to do your job. Vets are not going to trust you.”

McDonald was in Los Angeles as part of the VA's effort to track down and provide housing for homeless veterans when the exchange occurred.

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"Special Forces? What years?" McDonald said to the man. "I was in Special Forces."

McDonald served his country with distinction, unlike many of the scoundrels Anderson has unmasked. But while he was formally recognized as a graduate of Ranger School, he never actually served in a Ranger battalion or other special-ops unit.

On Tuesday, McDonald told reporters he misspoke while trying to "connect" with a homeless veteran.

“I made a mistake and I apologize for it,” McDonald said. "I was talking to a homeless veteran, I was trying to get that homeless veteran, if they were a veteran, the care and services they needed."

Anderson's group has reviewed hundreds of cases, finding everything from faked injuries, misstated claims of ranks and awards to military careers made up out of whole cloth. Ironically, Anderson said one group often relies on him to check out the claims of veterans seeking disability benefits: the VA.

“I often get calls from VA officials,” Anderson told FoxNews.com. “They have candidates filing -214- forms [discharge papers and separation documents] and they often reach out asking how they can determine how valid their claims are about service.”

Anderson says he has fielded a steady stream of calls from case workers at regional VA centers asking how they can spot a faked or forged -214- form.

Anderson has spent the past five years investigating those who claim military service, posting their stories on a “Wall of Shame” on his website. One recent induction was a Tampa, Fla., man who claimed in an effort to collect benefits that he was deployed up to 15 times to the Middle East and that he earned a Distinguished Flying Cross and Purple Heart. In reality, he was discharged from the Army after four months back in the early 1990s.

Another alleged example is former Idaho Army National Guard soldier Darryl Lee Wright. According to the FBI, Wright collected more than $250,000 in benefits he was not entitled to after falsely claiming that he suffered a traumatic brain injury in a 2005 rocket attack in Iraq. Prosecutors allege Wright was never injured during the attack, and the case is still pending

“People often say that stolen valor is a victimless crime and to some degree it may be,” Anderson said, “But often times the VA is paying out money to the wrong people and many vets who truly need that money are not getting it.”

Over the years, several celebrities have been outed for lying about their military careers. Tim Johnson, the former manager of Major League Baseball's Toronto Blue Jays was forced to resign in 1999 after admitting he had made up stories of serving in Vietnam when, in fact, he had been in the Marine Corps reserves throughout the war.

Among the several politicians who have been called out for lying about military service is former Rep. Wes Cooley, R-Ore., who in 1994 falsely claimed that he'd served with top-secret Special Forces in the Korean War, but that his military records had been destroyed in a fire. When a newspaper exposed his phony claim two years later, he backed out of a re-election campaign.

In 2010, Sen. Richard Blumenthal, D-Conn., was exposed for stating on several occasions that he served in Vietnam when he had been in a Marine Reserve unit that was never sent overseas. And the same year, Sen. Mark Kirk, R-Ill., was forced to admit that he'd never been the "Navy's Intelligence Officer of the Year," but that the award had been given to his entire unit. Both Blumenthal and Kirk are in the Senate.

In 2012, Tim Poe, a contestant on the TV show "America’s Got Talent" claimed to have suffered a traumatic brain injury while deployed to Afghanistan. After Poe’s first episode aired, viewers determined that although he had served in the National Guard, he was never wounded.

In December 2006, President George W. Bush had signed the Stolen Valor Act, which broadened the provisions of a previous federal law regarding the unauthorized wear, manufacture, or sale of any military medals or decoration and made it a federal misdemeanor to falsely represent oneself as receiving any decoration or medal. The Act was struck down in 2012 by the U.S. Supreme Court, which held that the Act violated the First Amendment. In 2013, President Obama signed an amended version of the law, making it a crime to falsely claim any military honor with the intent of obtaining money or any other tangible benefit.

Perry Chiaramonte is a reporter for FoxNews.com. Follow him on Twitter at @perrych