It's like this: when jury panels are summoned for trial week, there are about 200 jurors summoned for each trial, depending on the track record in that particular county.
You've got some no-shows, you've got some who're disqualified by age, disability, or felony conviction. They'll send 48 down to the courtroom for your average civil trial, 72 for a criminal trial. More if it's a high-profile case. If they don't get twelve, they'll call for a supplemental panel. (If your county has "one day/one trial" the numbers change, but that's usually only in very large urban counties where they have high numbers of no-shows and disqualified veniremen).
Only 12 will be selected to hear the case. The chance that somebody with strong principles and sufficient gumption to be a holdout will happen to be selected for a case that involves an obviously unjust law is small.
Your energy is far better spent (1) electing good judges who will hear a constitutional challenge at the proper time; (2) electing good and honest DAs who won't prosecute junk cases; (3) electing good legislators who won't pass unjust laws in the first place.
THAT is where educating people will have the best effect, because educating the general public about a theoretical proposition that cannot be supported by either a jury charge or anything but the most subtle of arguments -- on the off chance that they will be summoned, and then be one of the minuscule number who actually wind up serving on a case involving an unjust law -- is not as cost-effective as educating the vast majority of people who all have a vote on election day.
You would also better spend your time and money donating to or working for groups that campaign for better laws. Since RKBA seems to be your favorite cause, donate to your local gun rights group. GeorgiaCarry.org here has done a tremendous job at the legislative level to clear up ambiguities in the law, and they have also funded numerous challenge cases in the courts, with some success. They get the most bang for their buck of any outfit I know. Their president is a first class lawyer and a man of honor whom I am proud to know.
It's certainly cost-effective for the defendant in the case if a principled juror saves him from years in prison. What does "cost" have to do with it anyway?
Your energy is far better spent (1) electing good judges who will hear a constitutional challenge at the proper time; (2) electing good and honest DAs who won't prosecute junk cases; (3) electing good legislators who won't pass unjust laws in the first place.
What good does a Constitutional challenge do for someone who's being threatened with 15 years in prison if he doesn't knuckle under to the prosecution's demands? What good does an election do for the victim of a junk case charging an unjust law?
Educating jurors about their rightful powers to do justice doesn't take place in a vacuum, or to the exclusion of these other efforts, in any case. I'm on the Board of Directors of my local gun rights group, as it happens.
And as you could see in those two cases I posted, a jury doing justice in spite of the law is not a "theoretical proposition" by any stretch of the imagination.