Good point. And I'm sure if the court is in session, talking out of turn about anything (including jury nullification) would get you held in contempt of court.
So, saying you'll be arrested for talking about jury nullification in court doesn't really give an accurate picture. Though it is probably technically true.
"F@$% you, your honor!”
“Bailiff, please arrest mr. nthj for contempt of court”
http://en.wikipedia.org/wiki/Contempt_of_court