The bug in question: > From all this information it seems that Dropbox client first deletes files locally before it informs the server about the new selective sync settings. Consequently, if the client crashes or is killed before the server is contacted, the files remain deleted without any trace. After the client restarts again, it only sees there are some files missing and syncs this new state with the server. It c…
No, it's "you shouldn't trust one single thing with your data". Hardware fails. OSes have bugs (OS X's "space in your drive name and we delete your user folder.") Services have unexpected gotchas. This is why you never store anything in only one place.
A sync service by definition is not a separate place (unless he had found a bug in the Packrat feature)