I was recently summoned for jury duty and initially selected to be on the jury for a criminal trial that was expected to go through Tisha b'Av. If I were selected, what issues would I face in serving jury duty on that day? Suppose I was able to go to an early minyan and say kinot before the trial begins. Would it be permissible to sit on my chair in the jury box? Any other issues?
As it happens, the judge immediately consented to excuse me when I told him a bit about the very strict prohibitions of Tisha b'Av and that I would likely have difficulty concentrating on that day.