"...Wait, so they plead not guilty to get a court date and then plead guilty once they got to court?"
If you plead not guilty, you get a trial. If you are found not guilty, you are let off. If you are found guilty, you are sentenced.
If you plead guilty, you are sentenced.
"...Would the fine be heavier than paying the ticket itself?..."
Yes, of course, unless you did not which then in that case it would be.
(My answer makes as much sense as your question. What are you talking about?)