There aren't a lot of BYU fans here, and some of those are what I would call casual sports fans. I'm one of the few rabid BYU fans. We have an Air Force base in our area, so we get LDS members here with all sorts of sports allegiances. There have been a few Ute fans. None of them were unbearable or obnoxious, and one of them was actually pretty decent when it came to talking about the rivalry. He even invited BYU fans to come watch the 2006 BYU/Utah game at his place. I wasn't there (I was hosting my own viewing party), but I heard that he was obviously devastated by the Beck to Harline throw but still took everything in stride.
A few years ago we had one big Ute fan in our bishopric who wore a Ute tie to church all the time. That's okay, but one Sunday he acted like a jerk when he conducted Priesthood meeting. It was at the beginning of the summer and there was a college student there one Sunday for the first time. When he introduced himself in Priesthood meeting he explained that he was attending BYU and was in town for a couple of weeks on an internship. The Ute counselor made a snide comment about the student's being from BYU and said, "But I guess we'll let you stay." There was no "just kidding" or smile or anything to indicate that he was just having fun. The student looked like "What just happened?" so I piped up and said, "Don't mind him--he's a Ute fan." The counselor didn't say anything because I think he realized how stupid he had been to act the way he did. By the way, that counselor's daughter went to BYU-Idaho.