A counterpoint is that Japan's emperor had to be translated when he addressed his citizens about Japan surrendering in WW2. While he spoke Japanese, he did not speak Japanese any common non-royal Japanese could understand.

This isn't much different, the goal is to convey the ideas and/or goals of the document to those that do not speak the language, in this case the same language the document is written in (human language that is, not legal/vs non). It is a good start too, more companies need to do this. If they spell out things such as: arbitration is us just not wanting to go to court, not as a way to sue you, it greatly reduces the invectives that people will assume about the company.

While it might be "obvious" to someone that can read legal print, conveying the goals in regular language to the target audience is in my opinion long overdue in the legal world. Yes it won't convey every minute nit-picky detail.

Just like translating "saudade" from Portuguese to English as lets say nostalgia is likely wrong and not 100% accurate, it will at least get the general point across to a non-portuguese speaker.

http://en.wikipedia.org/wiki/Saudade if you've never come across the word before. One of my favorite words for an emotion.