He did not collude with known terrorists, place a series of mysterious phone calls to foreign countries or receive an unexplained sum of money.

Stephen Hayes’ mistake was purchasing an airplane ticket to Turkey.

The journalist and Fox News contributor bought a one-way ticket to Istanbul where he was due to board a cruise ship. That seemingly innocuous act landed him on the "no-fly" list, a component of the broader government terror watch list, and curbed his ability to fly. He was kept off of 12 subsequent flights during the next 6-to-8 weeks.

In exasperation, Hayes filled out numerous forms for the Department of Homeland Security and the FBI, trying to take all appropriate measures to prove he was not a terrorist and get himself off the list.

All to no avail – until he received an assist from a colleague.

“The way I got off of it was, Bret Baier on Special Report, was hosting Homeland Security Secretary Jeh Johnson for an interview that was to be largely about immigration,” Hayes told Fox News. “And at the end of the interview, Bret raised my case and said, ‘Mr. Secretary do you think Steve Hayes is a terrorist?”

After that conversation, something changed: Hayes is no longer on the list.

A secret list

The Obama administration’s suggestion that people on the Transportation Security Administration’s no-fly list be barred from owning guns made sense to many – at least at first.

“What could possibly be the argument for allowing a terrorist suspect to buy a semiautomatic weapon?” Obama asked the nation on Sunday during a prime time address following the San Bernardino terror attack. “This is a matter of national security.”

Some GOP presidential contenders and members of Congress even spoke in support of the idea.

But critics say not so fast.

They note the no-fly list is a secret one, doesn’t need to be explained or justified by the TSA and contains the names of many people who have never been charged or even formally suspected of any crime.

"The no-fly list at best is a blunt instrument to protect air travel, at worst a denial of the ability to travel without due process," said Cornell Law Professor William Jacobson. "That blunt instrument becomes even worse when used to deprive citizens of their explicit 2nd Amendment rights based on random and often secret information. We would not apply such randomness to other protected rights, and we should not do it as to the 2nd Amendment."

Mistakes

In the past, embarrassing blunders have shown the sometimes confusing rationale behind placing an individual on a U.S. terror watch list, such as the no-fly list.

The no-fly list has included members of Congress – including the late Sen. Ted Kennedy, D-Mass., and Rep. John Lewis, D-Ga. Members of the armed forces, too, have been on terror watch lists, as have U.S. air marshals and journalists, like Hayes.

Some estimates say 40 to 50 percent of the people on that terror watch list have nothing to do with terrorism.

Constitutional rights

A more important factor, critics say, is those added to the list are not given due process. That means President Obama’s appeal to prohibit gun ownership for those individuals could be considered unconstitutional.

“The Supreme Court has held that the right to keep and bear arms under the Constitution is a fundamental liberty,” Judge Andrew Napolitano told Fox News. “It’s in the same category as speech and religion and travel and privacy. You can only lose it if you’re found guilty of a crime by a jury.”

Fox News’ Doug McKelway contributed to this report.