The Feature has a piece highlighting the dangers of automatic syncing: specifically, a case where a secret service agent using a Danger Hiptop had his account hacked.

We'll see more of this, as the devices we own and the networks we use make decisions and act on our behalf. Automatic syncing is a great user experience: look at Cognima's Safeguard product and how it explicitly acts without the end-user knowing about it (that's the whole point) in order to eliminate worries about losing your phone, address book, etc. But having private information (and privacy is in the eye of the owner: contacts or photos can be extremely confidential, depending on their content) shuffled around over networks without appropriate security carries risks.