I spun up a vm and ran "strings" on the blockdev and got this:
http://i.imgur.com/fJOxRN9.png
Some poor iPhone users in Portugal have no idea that the app they're using is backed by a webservice on a VM that gives its block storage contents to anyone who gives Digital Ocean a $5 PayPal payment.
If that isn't a data leak, I don't know what is.
But the dd thing is really embarrassing here, I mean I'd expect some data on shared hardware being recoverable using hardcore forensics, but there are enough levels between hardware and dd that using at least one of them to make old data inaccessible should be both possible and pretty cheap.
"scrub_data Optional, Boolean, this will strictly write 0s to your prior partition to ensure that all data is completely erased."
If I didn't already know about this issue, I would never Have thought that leaving this option out would leak all of my data. My reading of the above option would be that, with it off, they would leave your data on the drive until it was reused, leaving open the possibility that e.g. the FBI could seize the equipment in the meantime and access it.
The opposite of "write zeroes to your partition" is not "give all of your data to the next customer".