http://craigmedred.news/2016/03/31/a-third-iditarod-assault/
It seems this is more common than originally made the news. Snips from the article:
As alleged Iditarod assailant Arnold Demoski from Nulato was settling into a cell at the Fairbanks Correctional Institute on the evening of March 13, an attack on at least one more Iditarod Trail Sled Dog Race musher — and possibly more — was underway along the Yukon River.
Several mushers have independently recounted an incident along the frozen Yukon wherein Stokey was approached by men on snowmachines who tried to pull her off her dogsled. All of the mushers asked their names be withheld for fear of retaliation from the Iditarod Trail Committee.
“Actually about six mushers were involved, four of them women,” he said. “Two snowmachiners pulled up on either side of her and tried to pull (Stokey) off her sled.”
Another musher, according to Rasmussen, “hollered to her, ‘grab your ax and use it'” to drive the men off. Iditarod rules requires mushers to carry an ax in their sled as part of their traditional survival gear.
That the Stokey incident passed unnoticed by the media horde covering the race is not surprising. The Iditarod is informally divided into two classes of mushers: contenders and the BOP — shorthand for back-of-the pack. Almost all media attention these days focuses on the race leaders.
The BOP is left alone to struggle north largely out of sight as it tries to stay ahead of Iditarod officials looking to boot mushers for going too slow in order to get the race over as soon as possible and thus cut down on costs. The Iditarod lasted just under two weeks this year, about two days less than a decade earlier and a week less than the 1980s when it was not unusual for the last musher to take three weeks to reach Nome.