If you don't know any math and I explain you why 1 + 1 = 2 and you get it, it's not because you decided to understand. You helplessly did so and you can't unlearn it anymore. There's no free will in that.
This same applies to the judge and jury. If they truly understand the illusion of free will it will have an affect on how they relate to other people. You simply cannot blame them for their actions the same way once the illusion is broken. It's like knowing the stove is hot and still touching it. You can do it but you'll get burned and no matter of how hard you want to believe it's cold it just isn't and every attempt to live your life like it is just results in you getting burned again and again.