I agree, check that out !I firmly believe that Xanterra's policy is illegal. I would personally carry in violation of their policy. I'm not telling you what YOU should do. Having to defend yourself before ignorant, arrogant elitists is a pain in the ass.
Xanterra may be a private company, but they are contracting with the government to service the public on public lands. They do not have same rights as private property owners.