I understand why SVG said, what he said. He is making a preemptive strike, so that the agent can't sell his story, that someone ran away from a promise to Prince.
But it was well known, that Prince was seeking a buyout from Boston (it's been written several times on Celticsblog), so Detroit really can't have been unaware of this.
Furthermore it can't surprise Prince or his agent, that Detroit wants to keep him. They are fighting for a playoff spot, and they have given up Singler and Jerebko. Why would they let him leave. Besides he really is a great fit for them, if he isn't too angry to play for them.
All in all Prince should blame himself for not thinking this through. Did he he believe that Detroit would buy him out "for old times' sake"?