Based on the info here I didn't even find the juror to be a punk. He apologized, then explained why he yawned. The judge didn't like it, and instead of lecturing the guy, he finds him in contempt? That's the definition of "punk" and "judicial arrogance" to me.
I just did a day of jury duty in the Cook County system. It was worth $17.20 for the day and it was boring. The legal system is kind of screwy that way.
It's not that he yawned, it's the way he yawned. When I yawn in public, I try to be as inconspicuous about it as possible, this guy obviously wanted to send a message that he didn't want to be there.
It's generally considered rude to yawn loudly in public. I don't know about a $100 fine, but the judge wasn't wrong to take exception to it. It's called maintaining an appropriate environment for some very serious business. How would it bee if the entire jury pool yawned loudly? Civility-- there's a serious lack of it.