It is the kind of Halloween party that has sprung up in recent years. Instead of going door to door, costumed kids congregate in a parking lot, where they gather goodies from every car.
The flier gave the church's address, then urged neighborhood children to "wear costumes" but added, "please no masks or cross-gender dressing."
The focus on gender was "fear-mongering and hate driven," said Smith, who has lived up the street from the meetinghouse for five years. "I have several friends who are transgender or drag queens for a profession."
It also made her question the motives of her LDS neighbors, she said.
"Putting something like that [in the flier] wouldn't make everyone feel welcome like my friend's daughter who wants to be Spider-Man."
If her son, now 2 years old, decided to wear pink one day, Smith said, there may be kids in the neighborhood who would no longer be his friend.
"I was ashamed of my community," she said, "so I posted the flier on Facebook."
LDS Bishop Dennis Toone leader of the Crescent 16th Ward, which hosted the party did not write the flier, but he defended the prohibition against cross-gender costumes, saying "it's church policy."
Actually, it's not.
The church's handbook does discourage the wearing of masks, due to "security and safety reasons." It says nothing else about costumes.
"The flier," LDS Church spokesman Scott Trotter said Friday, "does not represent church policy."
Toone explained that "we thought it was a church policy," adding, "I'll defend the church, and anybody who doesn't like it doesn't have to come."
The Mormon party organizers likely did not intend to hurt any nonconforming or transgender kids, said Jude McNeil, who directs research and training at Salt Lake City's Pride Center. They were just unaware of the potential consequences of such guidelines.
But the impact was the same, she said. "It's sending a message that it's OK to discriminate against people based on their gender expression."
And that, McNeil said, makes these kids feel there's no safe place for them even at an innocuous Halloween party.