It's a hallmark of every Australian election. Warning: This story contains an image of a Nazi symbol. Thousands of campaign posters — cable-tied to fences and lining the streets — each emblazoned with a candidate's name and portrait. And while stealing or vandalising corflutes isn't new, political experts are warning dirty tactics are becoming more common in some tight electorates. Election signs have been marked with swastikas or offensive slurs, burned, vandalised, smeared with excrement, stomped on and shredded, especially in marginal seats. A vandalised corflute promoting Zali Stegall, Independent candidate for Warringah. Supplied ( ) A corflute promoting Warringah...