I can't follow your logic on what the jury can/cannot do . It appears that the jury in that "case" wasn't sequestered. Why couldn't Fonda get his own knife? The jury doesn't do the investigation, it sits in judgement of the LE investigation.
Do you think that juries don't talk about their own ideas in the jury room?
They do, but always within the testimony and evidence.
Who's there to "slap their wrists" if they do?
Your co-jurors will send a note to the judge, "jury tainted" -- mistrial. Some other citizen gets to do what you failed to do.
Okay, thanks. As I've said, I've never sat on a jury.
As I said, the only time I was called, the venue was changed. It was Murder Most Foul - a man who had killed his wife and his business partner with strychnine - like something out of a Victorian novel.