The most anyone said was that what havoc did last age would be done to them, how can anyone have it coming to them more than if they did it themselves.
And yes kingdoms have profited from GBs before, I particularly remember SG gaining a lot from waving into a GB in age 45 or so (whatever age it was that pulse won land) and they took a pretty extreme lead out of it, before the got deleted en masse for xlogging. I also never said it was ok because it hpapened before.