Yes and no. Yes they posted this on Flicker which can be searched for by the public, so to me its legal. But some people in the pictures may not have been informed about the posting of Flicker. But in that cause the issue is on the poster and Flickers hands. We can't know those sort of things, and the parties knew of the camera, and lets face it some parties in the pictures have posted pictures on services like this before, so they should have known.
Another thing to note, most of the pictures were taken at San Diego 2006, which is a open to the public convention.