It would prove elders do not follow the elders' manual and wts literature when it says to MYOB, be compassionate, not DF people who are repentant, not DF people for being victims of sex crimes, and various other rules that are violated routinely.
It would prove elders way overstep their boundaries by asking intimate details of sexual "wrongdoing", such as asking who was on top, if lingerie was worn, if there was an orgasm, etc.
It may open them up to lawsuits. (not sure about that, just a thought)
It would show they cause, by their inaction, sex crime perps to have continued opportunities to perpetrate.
Basically, having JC meetings taped would cause a mass exodus from the WTS and terribly negative media coverage. It's a great idea for people to start taping the meetings.