The jury is shielded from any interaction with the random public. When they are moved from the courtroom, they are immediately taken to the jury room, and when they leave the jury room to go elsewhere, the corridor is cleared to ensure they have no contact with random members of the public.
Hypothetically speaking, even IF a juror saw someone flip the middle "finger of affection" to JA or to anyone else, I think the jurors have enough common sense to know that he was just a dumb kid who needed to be taught some manners & respect for the Court.
If the middle finger of anyone disturbs this jury (and would sway them one way or the other), then the Court has more serious concerns than the adolescent actions of the bird-flipper.
MOO