Ammm... There has always been a tradition of heckling at political events through U.S. history. The Bush campaign has decided not to allow an ounce of it for fear of the truth, for fear for an opposite opinion. These are public events. You are allowed to shout out at campaign events. (I have worked on over 20 campaigns both Dem and Rep). Most of the time the speaker will respond as it is the tradition. The Bushes have decided they are too good for the 50% of the Americans that question their policy.