Why? That source said the two parties had agreed among themselves before the debate that only family would sit in the family box.
The source described a tense scene playing out minutes before the debate began. As organizers waited for Trump's motorcade to arrive, an aide on the commission got wind that his campaign wanted Bill Clinton's accusers to be in the family box.
Kathleen Willey, Juanita Broaddrick, Paula Jones and a woman, Kathy Shelton, whose rapist was defended by Hillary Clinton as a young lawyer, appeared with Trump immediately before the debate at an event that was livestreamed on the Republican nominee's Facebook page.
Commission co-chair Frank Fahrenkopf went to the Trump staff room, knocked on the door and told the staff that the women could not join Trump's family in their box. Fahrenkopf told them that if they tried to, security guards would prevent them from entering the box, according to the source.
The idea was so closely held in Trump world that the staffers in the room, including a Trump lawyer, didn't know what the Trump team was planning for the women.
At that point, the debate commission co-chairs had to go on stage to welcome the audience. The Trump motorcade had not yet arrived, but Fahrenkopf instructed aides to tell the entourage when it arrived that the women would not sit with the family.
Later, the Trump team tried to justify the move by saying that billionaire Mark Cuban, a Trump antagonist, was allowed to sit in the front row during the first debate in September -- though that's not the same as the family box.
News of the thwarted plan was first reported by The Washington Post.
Trump campaign manager Kellyanne Conway did not dispute the story during an interview Monday with CBS "This Morning," but she said the family box was actually a "VIP box," and that the team had originally thought that the campaigns could choose who sat in those boxes.
"In the Clinton box they invited Sen. Claire McCaskill of Missouri, and she is not a family member," Conway said. McCaskill, too, was denied a seat in the family box.
"But they threatened to have security remove the women. I thought that was unfortunate because Mark Cuban got to sit where he wanted to sit," she said in a reference to Cuban's front-row seat at the previous debate.