User blog comment:Godisme/Kill The Shadow/@comment-5441712-20120613194842/@comment-2048489-20120614002010

I have a sneaking suspicion that it's going to turn out to be his (now nonexistent) hollow power somehow. The same thing cropped up during that anime-arc-which-must-not-be-named. Totally random idea thrown out there, but it might very well be that the fullbring theory is partly true. Those "seals" seem to be calibrated specifically to take away a bankai--why else would they specifically notice that the "Bankai" is gone, and not their powers in general? And like everything that has such a narrowed focus, if something is JUST different enough from what the "seal" is supposed to pounce on, it just won't work. And Ichigo is hardly your average Shinigami. Come on; he's human, shinigami, hollow, and fullbringer (albeit formerly for the last two), so something that works against shinigami is not guaranteed to work properly. Although, notice that Ichigo's Bankai DID react to the stealing, but it was hardly what on would call effective. Easiest explanation out there, surely, but by no means the correct one. As of now, it's purely speculation, albeit reasoned speculation.