Those who planted the bombs at various cities have one thing in common - none of the bombs tried to kill/maim the wealthy, the powerful and the politicians. They were after the vegetable and fruit sellers on the roadside. What happens if you kill/hurt a common man, nothing. Things move in a slow pace. They are given a few lakhs of rupees and forgotten. If they, the terrorists, had killed/hurt(even minor injury) an elite class citizen, they would be either have been decimated or behind bars by now. So they, the terrorists, who are also human beings and fear for their life, do not want to target somebody that may prove suicidal to them.