"People in an open society do not demand infallibility from their institutions, but it is difficult for them to accept what they are prohibited from observing," they said.
The 9th Circuit sent the case brought by Leigh's advocacy group, Wild Horse Education, back to U.S. Judge Larry Hicks in Reno last year to determine if the BLM limits are constitutional.
Hicks ruled in 2011 that a balancing of the interests of the agency and public access to a roundup in Nevada didn't warrant granting an injunction to block the gathers. But a three-judge panel of the appellate court ruled he failed to determine whether those restrictions violated First Amendment protections.
"When the government announces it is excluding the press for reasons such as administrative convenience, preservation of evidence, or protection of reporters' safety, its real motive may be to prevent the gathering of information about government abuses or incompetence," Appellate Judge Milan Smith Jr. wrote in the 18-page opinion in February 2012.
BLM spokesman Tom Gorey said Tuesday that the agency had no comment on the latest filing. Agency officials testified at a hearing earlier this year that they do their best to provide public access to the roundups and temporary holding of the animals and denied Leigh's claims she was singled out to be kept away from the mustangs.
The National Press Club, Nevada Press Association, Reno-Gazette Journal, The Seattle Times Company, the Las Vegas-Review Journal's owner Stephens Media and others joined in the new brief arguing that journalists routinely face far more dangerous assignments, especially at war. They say reporters should have the same unrestricted access to public rangeland as they do to battlefields.
BLM's concerns are "speculative at best and at worst are overly broad and ambiguous, often arbitrarily and capriciously chilling visual journalists' ability to cover matters of public concern," they said.
"If they are willing to assume such risks in a warzone, it should certainly be considered that such safety concerns by the government are nothing but mere pretext when it comes to horse gathers ... BLM land is more akin to an open park than a battlefield, and a horse gather is less dangerous than open combat or fires, floods, explosions and other calamities where safety concerns are at stake."
Hicks said during a hearing earlier this year that he recognizes it's an issue that "strikes deeply in people's emotions and interests."
"I also recognize the government is placed in a difficult position. It seems no matter what they do, they are going to be subject to certain controversy and challenges," Hicks said.
The journalists said Hicks effectively "rubber stamped" the government's assertion that the observers were allowed reasonable access even though they were prohibited from witnessing certain aspects of the gather. They said courts routinely have ruled that such limits are illegal when it comes to keeping TV cameras out of courtrooms or prohibiting videotaping of police activities.