User blog comment:Black Leg Sanji/Strawhat's New Bounties/@comment-66791-20101031033817

With the exception of Luffy, Franky, and possibly Robin, the Straw Hat Pirates haven't done anything over the past 2 years to warrant an increase in their bounties.

I'm not sure if it was ever discovered that Franky was responsible for Dr. Vegapunk's main lab, but if they did, then his bounty would have DEFINITELY gone up, since Dr. Vegapunk is an important figure in the Marines and the World Government itself.

Also, Robin's been on the run from the World Government for a long time. Seeing her with connections to Dragon himself, in addition to being with Luffy, would definitely cause an increase in her bounty.

As for everyone else...

Zoro: I doubt Mihawk would tattle on Zoro to the World government... Since he's obviously too cool for that, and since when has he ever been truly obedient to the WG anyway? Nami: She's been on a Sky Island for 2 years. When will the Government think of increasing her bounty just for causing some trouble up there? Usopp: The WG only knows him as Sogeking, plus he's on a relatively secluded island. Sanji: Since Ivankov is a revolutionary, he would likely have kept his own whereabouts a secret, as well as anyone with him, including Sanji. So, no one would know... Chopper: Still believed to be the Straw Hat's pet. Brook: As seen in a recent chapter, his bounty is still the same, but now that they know he's still alive AND associated with the Straw Hat Pirates, they might increase his bounty and change his picture now.

Point is, most people believed the Straw Hat Pirates to be dead over the 2 years they've been separated, so other than Luffy, most of them would not of had their bounties increased... Yet.