United said that they "have the right to refuse transport for passengers who are barefoot or not properly clothed"

Shannon Watts, a mother-of-five from Colorado and founder of movement Moms Demand Action, shared on Twitter Sunday that young passengers boarding a flight from Denver to Minneapolis were told they could not board the plane unless they changed their outfits.

Although some were allowed onto the plane after modifying or changing their outfits, she tweeted that two girls were not allowed on the flight. Of the group, she noted that one was about 10-year-old. Watts asked United for an explanation.

United responded to Watts on Twitter, writing that they “have the right to refuse transport for passengers who are barefoot or not properly clothed.” They later clarified that the girls in question were “pass travelers,” or travelers flying on comped or discounted tickets, typically reserved for employees and their family members. United explained that they have a stricter dress code for pass travelers as they are representing the United brand.

Still, stars like Chrissy Teigen and William Shatner joined the list of people speaking out against United’s confusing policy on Twitter.

“I have flown united before with literally no pants on. Just a top as a dress,” wrote Teigen, 31. “Next time I will wear only jeans and a scarf.”

Patricia Arquette also shared her thoughts on Twitter.

“Why aren’t you allowing girls to wear leggings on flights?” she wrote. “Who is your gate agent policing girls clothing? “Was there something’s strange about all these girls leggings? Do U understand U have just made at least half UR customers very unhappy?”

“Leggings are business attire for 10 year olds. Their business is being children,” the actress continued. “Y did dad board wearing shorts? Shorts R only business attire 4 Angus Young.”

“Turns out United bans leggings, torn jeans, and shorter shorts for free employee pass tickets. Still @united should update policy,” she added.

Actor Andy Richter wrote, “I have flown numerous times while displaying an egregious mooseknuckle. What’s a male over 10 have to do to get noticed?”

Comedian Sarah Silverman said that she was not going to fly on the airline for her upcoming tour.

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“I fly a LOT,” she wrote. “About to go on tour all April and changing all my @united flights to other airlines.”

Despite the outcry, United held firm that they were following policy.

“The passengers this morning were United pass riders who were not in compliance with our dress code policy for company benefit travel,” the airline responded.