Caught! From the Sun-Times' "Eye on Rezko" blog:

U.S. Sen. Barack Obama has someone attending the Tony Rezko trial.

A woman sitting in on jury selection was identified as attending court "for Obama," when a courtroom security officer asked all the people in an overflow courtroom to identify their organizations.

I had just asked the woman sitting near me (who was taking detailed notes) for whom she worked. "Actually, I can't say right now," she said. Just then, the security officer asked everyone in the room what organizations they represented. He pointed to her and said: "I know you're for Obama," then continued. She looked at me sheepishly and acknowledged she worked for the Obama campaign.

Such courtroom watchers are usually sent in to keep their parties apprised of daily happenings at trial.