I ran into them in Teton National Forest just northeast of Jackson. They run in rainbow-painted school buses and VW minivans and go off the beaten path to squat as long as they can. They don't stay in the campgrounds but find some spot way off in the boonies to live their 60's hippie lifestyles. I think they're pretty harmless.
Except to the environment and downstreamers...
Some of them squatted on BLM land about a half mile upstream from our former Oregon place, itself 'already in the boonies' a few years ago. They left behind clothes, garbage, open-pit latrines, and a cache of supplies for a return visit That winter, the remains of one of their tents and some other stuff they had 'disposed of' was washed downstream onto our property.
They were also using open cooking fires during fire season, smoking in the woods, etc, all with total disregard for public safety, public health, or surrounding private property, some of which, of the more portable kind 'mysteriously' disappeared.
They kept a low profile, so we just thought there were the usual, though scruffier, hikers using the area. It wasn't until deer season opened that I found their recently abandoned site, at the end of a 'closed' logging spur road.
May not have been part of this group, but certainly related.