This is the explanation I got as to why Bo Bice was even on stage with Trey in the first place. This is from an article found on DMB's page.

"Also backstage at Bonnaroo to pass the time for artists, was a high stakes no limit poker tournament which featured Dave Matthews of the Dave Matthews Band, Bo Bice of American Idol, Trey Anastasio of Phish, Robert Randolph from his Family Band, John Prine, Pop Star John Mayer, Warren Haynes of Gov't Mule, Herbie Hancock, Chris Robinson of the Black Crowes, Chris Kuroda who has done lighting for Mr. Anastasio and Mr. Robinson and an out of place Keller Williams. "I was invited to play in this tournament by John Mayer. I had met him at the Jammy Awards in New York last month and we were able to bond again at Bonnaroo and he asked me to come along. I had no idea who the other players would be and I was kind of speechless once I sat down at the table. I did manage to knock Trey out of the game fairly early, but he was quick to buy back in. That took some of the initial pressure off" Williams says. The game lasted longer than expected. After the initial "buy back" by Trey Anastasio, the players decided not to allow any more "re-buys" once the game was in its third hour. The game lasted so long that both Warren Haynes and Dave Matthews had to perform, which put the game at a standstill. "I figured that since I was responsible for breaking the flow of the game up, I told the players that they could join me onstage to keep them from waiting" Matthews says- an offer that was only taken up by Haynes and Randolph.

Following the Dave Matthews Band set, the game continued and eventually found the underdog, Chris Kuroda taking over $400,000 by finishing in first. "Well, I am the least celebrity of them all, and I think I could use this money the most" laughs Kuroda. The game which lasted longer than expected took it's toll on fans as Trey Anastasio had to turn down sitting in with rock band, "The Mars Volta" during their set and due to Bo Bice being the third eliminated, he was able to fill Dave Matthews' agreement to sit in with jazz band, "Galactic" (which did feature DMB Violinist Boyd Tinsley on "Whole Lotta Love"). "I went from playing cards with four kids in Alabama to playing with these legends. It was a great experience for me and I have to thank "Idol" for that Bice says. "Maybe next year those guys can come sit in with me sometime when I have my band put together, but for now I'll live on the great memories that I had with these guys and the great memories I had playing this wonderful festival."

Trey must suck at poker. I mean just look at his poker face.