  I am sure it didn't used to be. Maybe the law has changed. It would be best to find out, first. That woman who troubled me seemed to think she could do so with effect!  It has never been illegal to spoil you ballot paper, if anyone botherd you about it tell them to F OFF:) and besides, how the hell did they know it was you?? you ballot paper is totally secret, if anyone broke the law the woman who hastled you did.