Very interesting. I know on movies North American Indians are portrayed as having this mystical attachments to burial sites and the resting place of ancestors. I would not want to denigrate something I am not sure of. But with that said, growing up very close to the Navajos and Hopis I found that the burial rites were important but I do remember any sacredness attached to the actual burial sites. I see no such evidence in the ancient sites like Mesa Verde and Montezuma's Castle or Tuzigoot.
Perhaps I am missing something but I think the priority on such things is a Euro concept. Sometimes we project meaningful things to us unto other cultures.
I hope I will learn more here. Certainly there could be differences in the differing tribes. Or perhaps Eastern and Western traditions within North America.