First of all, she shouldn't have been thrown in prison in the first place. What she did wouldn't have landed anybody else in prison. Second of all, ALL celebs get solitary when they go to jail. Want to know why? Because the rest of the inmates would tear them apart if they didn't. Tommy Lee got solitary when he was in. They actually wouldn't let him do anything with the other prisoners. He asked them why, and they said because another celeb who came in earlier asked if he could go out into the yard with the rest of them. He was out maybe five minutes before he got the stuffing kicked out of him.
So it's not like, "ohh I'm Paris Hilton, I'm too good to be with stinky inmates". They put her in solitary for her own safety.