Ok background on my theoretical madness here:
Ok here's my theory, we know that Spandam's intentions aren't exactly in the best interests of the world. We know that Aokiji's appearance at (forget the name of the island) inspired the Mugiwara to ask questions of themselves and their abilities.
Could it have been a test? could this have all been a plan by Aokiji?
We have to assume that in his time, he's witnessed the events surrounding Robin, especially from the goverment side, the bounty for false reasons, and the way she's moved from crew to crew. We also know that Kuzan heard Saul's last words and that while not being her ally hasn't exactly demonstrated his position as an enemy either. We know he knows of her abilities and so thus far hasn't allowed her to stray to evil and yet has still kept her out of government hands.
I lack evidence on him being behind the Aqua Laguna at this moment in time, but the second i find it i will resurrect this thread.
I feel that Aokiji feels he's killing two birds with one stone on this one; bringing CP9 back in line with the ideals of the WG and putting Nico Robin in safe and 'good' (as in kind hearted) hands.
Any takers on this theory?