We have several Utah long-time Utah residents who claim they have never it. You also now have about the same number (in this limited sampling) who claim they HAVE heard it in Utah.

Following from this point, you have Hypnotoad who claims to have never heard it, now shimmy (who apparently attended the same high school as Hypnotoad) who argues it was used at their high school, and the implication is that it was used there regularly.

You also have the evidence I provided of the search of CB, that shows many posts (several pages, actually) of people using the word. Now, we don't know where those CBers are from, but we can make the strong assumption those people all have Utah ties to some degree. This is the strongest piece of evidence in favor of my position--it is used by people with Utah ties, and it is used fairly commonly, but we can't be sure whether the Utah connection is a red herring or not.

While examining my CB search evidence, we also discover that Superkid about 2.5 years ago initiated a similar discussion about the word. He claimed to observe its usage commonly in Utah, and in that thread even more people (with Utah ties, presumably) also acknowledged its usage.

You also have 2 (exactly 2) who have said they've heard it outside Utah. However, they didn't clarify if they heard it from people with Utah ties or not.

"So it goes" asks he question if perhaps it's more of a Mormon thing in certain areas, which is certainly a possibility, but this does not negate the possibility of Utah being the source, or at very least a promoter of the word.

Now, including my own personal experience, as a non-Utah native, but one who has lived in Utah for 3 decades now (and also adding the hearsay testimony of my wife, who I interviewed on the topic after making this post, and who also has about 25 years of Utah experience), we have both heard this term in Utah many times. As transplants, I would argue we're more likely than native Utahns to notice different word usages or manners of speaking than Utah natives, because how would they even know what is strange?

Wrapping all of this up together, I think it's fair to conclude the term IS in regular use in Utah. The origination claim is dubious, but at very least it's clear many people with Utah ties use it. How common is it? Who knows, but the testimony of those claiming to never have heard it is questionable, not because they are presumed to be dishonest, but perhaps more their familiarity with it made it nothing of note to them (see the Hypnotoad-shimmy exchange). I suspect "So it goes" (I'm quoting his name to make clear that's a name rather than part of my sentence) is probably hitting close to the truth: this is a bit of a Mormon thing that may be also be in other areas where there are people with Utah ties.

Did I waste entirely too much time on this post? Yes, I did. Insomnia does strange things to the brain.