The BBC article quoted Anita on why she didn't attend the event, and I'll expand a bit.
Originally Posted By: Anita
Requested pat downs or metal detectors after mass shooting threat but because of Utah's open carry laws police wouldn’t do firearm searches.
Originally Posted By: tfabris
It's a clear admission by USU that they received threats and chose to do nothing about them.

The threats made against her were ones of violence by firearm. The school she was going to speak at was a public one, so it falls under laws that govern Utah. Those laws allow guns on public school campuses, and allow people with permits to conceal firearms on their person. They didn't choose to do nothing about it, they were bound by law to not do more as Anita asked.

Had someone with a valid permit attended, they would have been legally allowed to carry their weapon concealed and ready to fire into the venue where she was speaking.

Utah also allows open carry of firearms without a permit, and the police would not have been legally allowed to stop someone from entering with a visible weapon on them. The open carry law requires the ammunition to be two steps away from being ready to fire. With a modern handgun, this is literally less then a seconds worth of time to do.

The concealed permit side was a concern for Anita due to Utah being a "shall issue" state. This means that unless someone already has certain criminal convictions, the state has to grant a permit to anyone who asks. They also recognize any permit from any other state in the US, some of them have even less restrictions then the already lax ones in Utah.