Some issues have been raised before with bookmarks "dissapearing" or being deleted from the bookmarks bar randomly and the cause was assumed to be a too high drag/drop sensitivity on the bookmarks in the bookmarks bar. I just experienced a large bookmarks folder being deleted and i think it could have been prevented if a dialog box would appear if you try to drag and drop a bookmark off the bookmarks bar. It's not so bad if it's a single bookmark but in my case it was a folder with 30 well sorted bookmarks in it.
Safari has implemented said dialog box.
