I have more than a passing familiarity with the "prepper" types that are being discussed, and where and how Chad and the authors he helped get published got their start. It may surprise you just how pervasive this presence is throughout the Intermountain West and beyond. And how long it's been growing. But this isn't about my personal experiences with said groups. In answer to your question, and as an example in regards to this case specifically, even Sheriff Humphries was unaware of this presence in his area and was genuinely surprised to learn just how big of a movement it is. See 4:50-6:15 of this interview and note that he says Chad "did have a significant following" in the area:
When pushed for details on how big of a following Chad may have had the sheriff took a wild guess and said "more than 10." I'm going to go out on a limb and say he was greatly underestimating (whether intentionally or not) that number.
Now, to be sure, a lot of people have distanced themselves from Chad since this whole ordeal, but believe it or not they're still out there and a lot of them still believe in the crazy stuff Chad and others were preaching. Chad wasn't the first one to start believing that stuff and he wasn't the first to up and move to the area. He up and moved to the area because the "prepper" movement that he was a part of was already well established there and in the surrounding areas. And if you remember from the court proceedings he tried convincing others including MG and DW to buy some property and move into the area. It surely didn't take much to convince LV, AC, and MP to move there either.
Now would I believe there's enough of them around to potentially cause some problems for jury selection? I couldn't answer that, but I would hope not. Then again they very well may be just as upset that Chad's actions are a black mark on their prepper movement. Who knows?
All MOO.