Why? Because, according to her, she has cancer.
That's what she said in a video posted to Facebook that shows her group packing up from their Alaska Airlines plane as it sat at the gate in Hawaii.
"You're taking me off the airplane because I don't have a doctor's note saying I can fly," a woman is heard saying. "All these people are waiting, and I'm being removed as if I'm a criminal or contagious, because I have cancer and no note to fly."
Sedway did eventually get on a flight back to San Jose, California, although she didn't get home until late Tuesday night.
And she got an apology.
"We regret the inconvenience Ms. Sedway experienced ... and are very sorry for how the situation was handled," Alaska Airlines spokeswoman Bobbie Egan said. "... While our employee had the customer's well-being in mind, the situation could have been handled differently."
Her cancer fight notwithstanding, Sedway was in Hawaii in time to celebrate her 14th wedding anniversary. Still, on Monday, she was on a plane to head east.
Then, according to her Facebook post, an airline employee who saw Sedway seated in the handicapped section asked her how she was doing. The second time she inquired, Sedway wrote that she responded by saying she sometimes felt weak.
That was followed by a call to a doctor, then her removal from the plane.
Egan, the Alaska Airlines spokeswoman, acknowledged that the carrier's policy when someone has a medical issue is to call MedLink, a group of ER nurses and doctors. The idea, she explained, is that "it is better to address medical issues or concerns on the ground rather than in the air, especially on flights to or from Hawaii" -- which in that case would last five-plus hours over open ocean.
The decision to pull Sedway from the flight was done with "the customer's well-being" in mind, according to Egan.
Still, that doesn't mean it was the right decision. Alaska Airlines since apologized to Sedway "for the disruption this has caused," in addition to refunding her family's tickets and paying for their overnight accommodations."
Even though she was stuck in Hawaii, Sedway made clear on Facebook that this was a real "disruption."
"Because of this, I will miss my chemotherapy, my children will miss school and my husband will miss important meetings," she said.