A day after Politico reported on sexual harassment allegations against Herman Cain, reporters were banned from asking about that topic during an open discussion with the Republican presidential candidate.

Audience members will only be allowed to ask questions generally related to conference topic of 9-9-9, Jim Pethokoukis of the American Enterprise Institute, a conservative think tank that sponsored the discussion, tweeted on Monday. The conference, titled 9-9-9: A Discussion with Herman Cain, was about Cain's controversial tax reform plan.

One reporter, Jonathan Karl of ABC News, tried to ask about the sexual harassment allegations anyway, and Cain refused to answer, citing the ground rules my host has set.

After the conference, reporters were not allowed to leave the building until Cain had gone.

Cain Tenure at National Restaurant Association

A Politico investigation published on Sunday found that, while Cain was CEO of the National Restaurant Association from 1996 to 1999, two female employees with the lobbying group complained of sexually suggestive behavior by Cain that made them angry and uncomfortable ... and they signed agreements with the restaurant group that gave them financial payouts to leave the association. Under the terms of those agreements, the women were forbidden to talk about the incidents.

The incidents involved conversations allegedly filled with innuendo or personal questions of a sexually suggestive nature, taking place at hotels during conferences, at other officially sanctioned restaurant association events and at the association's offices. There were also descriptions of physical gestures that were not overtly sexual but that made women who experienced or witnessed them uncomfortable and that they regarded as improper in a professional relationship, Politico reported.

According to the report, Cain dodged several requests for comment before the investigation was published. On one occasion, a reporter approached him outside the CBS News studio in Washington after Cain had been interviewed on Face the Nation and asked him, Have you ever been accused, sir, in your life of harassment by a woman? Cain reportedly responded, Have you ever been accused of sexual harassment?

In an appearance on Fox News on Monday, Cain acknowledged the allegations but said they had been determined to be baseless.

I have never sexually harassed anyone, he said. I was falsely accused while I was at the National Restaurant Association.