Don't forget the 'trail tax'. Sentences are 10-20-50 years if you exercise your right to trial, while if you 'voluntarily' waive your right the plea put before you could be 1-5 years. Even if you are innocent, you are now at the point while in jail you already lost your job, your car, your house, are you going to risk that a system that did that to you already is going to give you a fair trial? Or are you going to go off of past experience that system is going to fuck you and just take the shorter bit?