From what I understand, many of the people that work at car shows as "reps" are not actual employees of the company. They are hired from an advertisement agency / marketing company. They are not permanent employees, although they might actually travel the USA to various car shows and represent the same company for the entire auto show "tour" that occurs. However, as these folks are just usually getting data from "bullet point lists" provided by the mfg, they are clueless.
As a HUGE Volkswagen and Audi fan, I can recall going to even the Detroit auto show in addition to the local, Cleveland, Ohio auto show. At both locations I would often see the same "hired help" and hear them spewing off the same inaccuracies to the general public. They are trained for the specific tasks at that show, and usually the people training them work for the domestic corporate and are equally as uneducated. You may be surprised to know that many people who work for auto mfg's don't actually like cars, or lack the passion that we have here on these forums.
All of that being said, that does not obviously excuse the mfg from sending half-truths into the wild. But for them to flow-down proper data, it takes a long time and is a daunting task. I'm guessing that Nissan Japan has yet to revise this data in such a way that it has flowed all the way down. For example, a month ago when my wife and I leased our 2012 Leaf from a local dealer, our salesperson indicated he has not personally delivered one (although his dealer had sold a few). He was less educated than I was on the car, which is not uncommon for sales people in this day and age. Sad, but true.
But alas, from what I've heard Tesla does the same thing. Promises ranges that are at peak conditions and unlikely for the average consumer. This isn't much different than the MPG ratings most cars carry. I rarely see those conditions on my ICE unless on the freeway using cruise control. Around town, my MPGs are always worse. Then again that might just be my lead foot... hahaha!!