I don't "send" documents to my Kindle. Not really because of any Big Brother paranoia, but simply because it feels so roundabout. I have the document right here on my computer, my Kindle is always right here within spitting distance of my computer. So why would I want to send my document on some Grand Internet Tour when the USB cable is the shortest (and quickest) distance between points A & B? But I understand perfectly that many enjoy the convenience of a document traversing many network "miles" to wirelessly show up on their Kindle that's five to twenty-five feet away.
So I just disabled Personal Document Archiving. I don't find it necessary to send my documents off to Boarding School before putting them on my Kindle.
I do think they probably should have made the intial default setting "Off" and then instructed people how to turn it on if they wanted it.
* NOTE* My post is all in fun. I don't begrudge anyone's enjoyment of Amazon's invisible—100's to 1000's of miles long—USB cable.