Some get burned, some don't. I would guess (and yes, this is a guess) that some sign of the hogan remains as a warning to others who may come into the area. In our first home on the reservation, it was said that the home was built on "Anasazi burial ground" by a medicine man. Because our home rested on this bit of death associated land, we were told that we had an "anasazi spirit" attached to our family. The family had a blessingway and that was the end of the matter. So, I would presume that even if the structure is long gone, death is still associated with the location itself.
There is a case in the Witch Purge of 1878 in Ganado, AZ that the original location of the Hubbel Trading Post was moved to the other side of town. This was because an accused witch was murdered on the steps of the original trading post. Hubbel, a non-Navajo, was heavily advised by local elders to move his post and he complied. You don't find this kind of discarding of homes nearly as much on the reservation today. This is probably why it seems like there are so many "haunted houses" out there. These houses retain a bad reputation long after the event and are often used as just temporary roosts for Navajo families...or rented to non-Navajo...lol.
Stephanie
In every man there is something wherein I may learn of him, and in that I am his pupil.--Ralph Waldo Emerson