First of all, I don't know why only in mumbai the voting marks are kept in the middle finger.
and almost every celebrities who came out of the voting booths, showed their middle finger - which also gives some other meaning.
However there was one exception, Our King Khan SRK. Instead of showing the middle finger, he showed the entire hand to the photographers.
...and when his team is losing in IPL at South Africa, this is a real good show from SRK!!!