At the moment I am reading this, several most recent (and, it seems, perfectly legitimate) comments have been downvoted to zero: one by Mz (http://news.ycombina

At the moment I am reading this, several most recent (and, it seems, perfectly legitimate) comments have been downvoted to zero: one by Mz (http://news.ycombinator.com/item?id=1189009 http://news.ycombinator.com/item?id=1189009), jacquesm (http://news.ycombinator.com/item?id=1189007 http://news.ycombinator.com/item?id=1189007), algorias (http://news.ycombinator.com/item?id=1189004 http://news.ycombinator.com/item?id=1189004), coryl (http://news.ycombinator.com/item?id=1188999 http://news.ycombinator.com/item?id=1188999), as well as arnorhs (http://news.ycombinator.com/item?id=1188988 http://news.ycombinator.com/item?id=1188988) and pbhjpbhj (http://news.ycombinator.com/item?id=1188906 http://news.ycombinator.com/item?id=1188906). And a few minutes later, they are now back in the positive. Could it have been a case of vandalism?