User blog comment:Blackendedsoul/The Authority of Admirals/@comment-4754162-20130708044042

Good spotting my friend, I have the same impression too, that Shichibukais "belongs" to the WG, and are only allies to Marines. I would go with the idea BadWolf suggested, Issho (or Sakazuki who commanded him) obtained authority to do so from higher up due to the publicized news of Law ~ Strawhat alliance.

Seriously if the Admirals already had this authority in the first place, Hancock would have been discarded for her actions during the War. Same goes with Kuma during Sabaody incident (which occured in the face of a present admiral - Kizaru!). The latter was arguable because of Kizaru's lazy attitude but just stating the possibilities. And Kuma did said something like "If its not in direct conflict with the interest of WG, then I had no need to explain my actions" to Kizaru during the interval of the separation.

There were times when people like Mihawk gave me the impression of alliance with Marines, because they ultimately had the choice whether to help them or not. That in itself spells "independence" in my opinion.