I guess your right in geographical sense. I was wondering whether to include Nuuk or not and decided not to just to avoid the debate, but I didn't even think of Hawaii... ;)
I think its safely in the America's because it is on the right side of the international date line. Maybe someone can measure the distance to the nearest mainland America's point and the distance to the nearest mainland Asia or Oceania point (not sure what the Oceania point would be). Nuuk is tougher, but I vote for Americas.