Graffiti Posters - a shot in the arm or a shot in the foot?

The Tory election poster graffiti spoofs are becoming the defining image of this year's Westminster Election Campaign. Many of them are hilarious, some make valid points, but isn't there is a danger that they are counterproductive?

Even when they take the P*** in the most provocative way out of the Tory Campaign, they draw attention to that campaign. When the "originals" are seen on bill-boards, people are more likely to take notice of them because they will have seen the spoofs.

On the principal that no publicity is bad publicity isn't there a danger that those who oppose the Tories are giving the Conservative Party a boost by drawing huge attention to the party's campaign posters? Isn't every reproduced poster a shot in the arm for the Tories and a shot in the foot for the parties who produce the spoofs?