So basically, charge someone with something ridiculous, and then be offer a sweet sweet deal, such as "only 6 months jail time and confess to 15 felonies. Oh and if you want to go trial it will cost you and your family years of drama, all your savings, and risk 50 years in prison". How nice of them! Let's suppose someone offers you this deal. Does it even matter if you're innocent? Your life is going to be messed up either way. Maybe you cave under pressure and take the deal. How is that furthering the cause of justice?
Oh, and in theory, there's this little thing in the US called the Sixth Amendment:
"In all criminal prosecutions, the accused shall enjoy the right to a speedy and public trial, by an impartial jury of the State and district wherein the crime shall have been committed, which district shall have been previously ascertained by law, and to be informed of the nature and cause of the accusation; to be confronted with the witnesses against him; to have compulsory process for obtaining witnesses in his favor, and to have the Assistance of Counsel for his defence"