Apparently they haven't ruled out random invisibility.
Climbing team believed missing
Seasoned pair didn't return from China trip
By MIKE LEWISP-I REPORTER
The owner of the Seattle-based guide service Mountain Madness Inc. and another elite climber are presumed missing after they failed to return from an expedition to a remote mountainous region of southwestern China near Tibet.
"The fact that no one knows where they are is consistent with climbing without a permit," said Eric Simonson, owner of International Mountain Guides.