I think some posters here have been concerned that a number of landowners in that area are not year-round residents and, therefore, either are not aware of Sherry's disappearance or are aware, but unable to search their own land at this time. That's where it would be helpful to have LE contact the landowners to verify that they are aware of the search.
Land ownership is very complex. In regards to issuing a public request for people to check their property, asking "landowners" is much less cumbersome terminology than asking land owners, renters, leasees, etc. Yes, there are probably a lot of land owners who are not aware of the case. Much of the land is owned by people who have never seen the land or have never set foot in MT or ND. Some landowners have not seen their land in 30 or 40 years. Quite a bit of the land is owned by people who live in the Phoenix area, or on the West Coast.
As farmers and ranchers retire or pass away it is quite common for the land to remain in the family, even though the family members no longer live in the area. Much of that land has passed though a couple of generations since it was actually worked by an ancestor. The owner gets a property tax statement from the county once a year, and check from whoever is renting the land. Other than that, they have no connection to the property.
Most of the farm and ranch operations run from several thousand to twenty thousand acres. But a look at a township plat map shows a different picture of the land. When the land was homesteaded it was divided into 160 acre parcels, one half mile square. That is referred to as a "quarter." A quarter is 1/4 of a section of land. A section is 640 acres in a square, a mile on each side. A township consists of 36 sections, six miles by six miles.
The 160 acre homesteads were not large enough to support much of a family so so over the years many of the quarters were sold to neighbors and farms became larger. But some people kept their land and rented rather than sell. As people passed away, often land stayed in the family but was divided among the heirs, so 40 acre parcels are very common.
When I look at my township plat map I see that about 2/3 of the land is owned by people who do not farm or ranch that land. Some of the owners live in town 15 miles away. Many owners are scattered across the USA. They are the grandchildren or great-grandchildren of people who once lived in the area.
However the people who rent or lease that land care for it as if it is their own, and they will search it as if it were their own. As I mentioned in the previous thread, I own land about 200 miles form where I live. If there was a search being conducted of that area it would not be practical for me to go down there and search it myself. But I do know that my renter would search it, and since he has been renting it for the past 30 years he actually knows the land better than I do.
I hope this helps explain a little about rural land ownership and why making direct contact with each land owner is not necessary.