The classic dick-n-balls sketch is not generally a unique identifier that on its own would invalidate the ballot paper: counting such ballots is not new. If you put anything on the ballot paper that can uniquely identify the voter then the vote is informal. A high proportion of voters would be the only person with that name that voted at a particular station. Initial counting will treat ballots containing names as invalid until the race turns out to be tight and the votes might make the difference. A handful of tight races end up with court rulings on whether a name is uniquely identifying or not.