With iCloud, there is no secret incantation, retina scan, or hacking involved. Your data just is. No longer will you have to consider whether the right folder is synced to the right app. Work on one device. Turn it off. Work on another device and pick up where you left off.
Ubiquitous data sync/access scares the crap out of command and control corporate IT environments. However, an enterprise rights data management strategy could mitigate most of the risks.