Don't know about the blocked off rows but I think quite a few airlines are going from 20kg to 15kg allowance. Certainly the charter airlines. Not sure if the reasons are 'green'/fuel saving or just down to money as most people going for a week in Majorca/Ibiza/Lesbos etc.... can't seem to go without taking 25kg of cr4p with them in coffin size suitcases!
Phil