The Bush twins came on right after the Kerry girls and yes, like the first two, there were boos and cheers.
The Kerry girls are getting all the notoriety because, IMHO, the press was very surprised anyone would boo a Kerry.
You are obviously not getting your news in Europe / from CNN International.
The story of the Booing leads off with the Bush twins being booed and then Kerry daughters - makes it seem more anti-Bush than it was. they are fair enough to say though (after the impression has been made!!) that the majority of the audience were probably more interested in music than in politics.