Why they are showing middle finger??

These are two pictures appeared on same day in The Hindu. First picture is of the leaders who voted in the third phase of the Lok Sabha elections are (from left) Uttar Pradesh Chief Minister Mayawati, BJP’s prime ministerial candidate L.K. Advani, and AICC general secretary Digvijay Singh, displaying the indelible ink mark on their forefingers. Second picture is of the Bachchan family outside a polling station in Mumbai, displaying the indelible ink mark on their middle fingers.

First of all i want to ask why they are showing middle fingers? Whether their votes would be in/valid, whether there was a different rule for them and whether they know or not that the gesture was vulgar. The normal standing instruction is that the ink should be applied on the left index/forefinger (though there are alternate rules in case the forefinger is missing or if there are no fingers in some disabled persons). SO, by this gesture the Bachchan family has not only offended election commission but also the entire nation. If in any case the ink was put on their middle fingers they should have avoided the gesture by showing all fingers.