Unfortunately for Comcast, representatives of an organization called Save the Internet were also there, and had their cameras handy. They took pictures of a Comcast employee handing out papers to the people they bused in. Later, some of the same people were photographed sleeping during the meeting. According to Save the Internet's website, "They arrived en masse some 90 minutes before the hearing began and occupied almost every available seat, upon which many promptly fell asleep."
A Comcast representative later acknowledged that they were responsible for bringing in these individuals, and also that the people seen with matching yellow markers attached to their shirts were identifying themselves for Comcast organizers. However, she denied that the company was attempting to keep out the public, stating that they were only there as surrogates for Comcast employees who had been encouraged to attend. In essence they were saving a a seat.
On one hand this matches one of the "seat warmers'" description of his duties. On the other hand, if we just took Comcast's word for things the FCC wouldn't be holding a hearing in the first place.