Cannabis is an unusual crop due to the fact that the most valuable part is an un-pollinated flower. In most other crops the harvested portion is either non-reproductive (like spinach) or pollination is necessary for either production of fruit (like squash) or seed (like sweet corn). The only other crop I can think of whose quality is destroyed by pollination is pineapple. The pineapple is native to South America; but the production is done in places like Hawaii because there are no natural pollinators (hummingbirds!) in Hawaii. In fact, state law prohibits hummingbirds on Hawaii as they would potentially ruin the pineapple industry.
Unfortunately, cannabis pollen is tiny (~20 micrometers) and is carried by the wind, not hummingbirds. This creates a problem for high value THC/CBD cannabis flower producers when they are growing in proximity to hemp fields. Seed and fiber hemp fields either typically have a significant percentage of male plants or are monoecious ('hermaphroditic'). Even CBD-oil "hemp" fields often have some male or monoecious plants in them due to their large size and lower intensity of management.
In the seed industry, cross-pollination problems are usually solved collectively though the voluntary use of a 'pinning map'. Seed growers in a given region will mark their fields on the map, and ensure that no fields that might contaminate their seed crop are within an agreed upon radius (which depends on the crop). Again, unfortunately for cannabis, we do not even know what distance is required to isolate sinsemilla crops from hemp fields. The distance required between two hemp seed fields is established - but is for a case where the pollen produced in one field will compete with the pollen produced from the neighboring field. No one really knows how far away a pollen producing field has to be from a field with no pollen in order to minimize seeding. And what level of seeding is acceptable for a sinsemilla producer?
Given the explosion in the number of acres planted to 'hemp' in Oregon, I expect we're going to hear a lot about sinsemilla crops that lost a lot of value due to neighboring pollen. In fact, our own fall quality control trials were heavily seeded. As a result, we're facing a possibly intense battle between the high-value, small-scale sinsemilla producers and the larger hemp producers. In my opinion, in order to protect the developing industry in Oregon, there should be a requirement that fields are carefully inspected and any pollen producing plants removed (we'd be out of business though, if there was not with the exception for males used for breeding and stock seed production).