Intimidation, browbeating? I mean, if there is anything to the Milgram experiment (and I believe there is), then many people will deliver what they believe are dangerous and painful electrical stimulation to somebody so long as someone in a position of authority behaves as if it is standard procedure. If those rates are truly 99.5% in 20,000, then maybe it's just because everyone is doing a great job - or maybe jurors are vulnerable to being herded along by (certainly knowledgable and experienced counsel) some very intimidating and powerful authorities. I doubt it is simply a matter of "overcharging is extremely rare, as judged by regular Americans".