Kiffin probably took Davis's last pudding or drank his prune juice or something. There's no way to know he's a liar. Your boy Howland left Pitt under contract to go to UCLA. Scottie's boy Self left Illinois and Jay Wright left Hofstra. It happens. Part of the job.
Bobby Petrino didn't even coach the Falcons for a full season.
Obviously people have to question Kiffin's loyalty, but USC was his dream job, it's hard for him not to turn the job down. I don't really understand USC hiring him though, he doesn't have a proven track record as a head coach, it's not as if he was amazing in his only season at Tennessee. We'll see how he turns out. But Roller, I still don't see how he lied in Oakland. And he was probably more loyal to the Raiders job than you think, but just like every coach with the Raiders, he was given very little time.