No, equal treatment for all
It doesn't matter who it is or what they have done or were accused of doing, people should be treated the same. It is unfair to allow money and status predominate how a trial should go. And lets face it, if we are going to start charging Justin Bieber with crimes, he is guilty of noise pollution!
They are citizens.
No, when celebrities, like Justin Bieber, are in court, they should not run the show, because they are just one of many citizens in court at that point. In court, the judge, and only the judge, is the boss. The celebrity may have a lawyer represent them, but they are no different than everybody else.
The Judge runs the show
The legal system is very clearly built on the premise that a judge presides i.e runs a trial. The idea of someone else running the show just because they're famous is absolutely preposterous and a horrific notion to boot. It would be an abuse of justice and a horrible precedent. Imagine if J Biebs was in charge of the legal system. I tremble in fear of the idea.
No They Shouldn't
I do not believe celebrities should run the show when they are in court. I believe Justin Bieber is having a hard time accepting the fact that his actions are bad and most people in America are very tired of hearing about his antics. I wish we could kick him back to Canada. Let them deal with him.