Not sure what the damage control would be for . . . if they announced a new land, even a new attraction at D23, more than just the top-secret Avatar stuff . . . I don't think fans would be upset!
The CM sounds like he/she has severe psychological issues if their goal was to "disrupt" a Disney fan convention. Isn't that like psycho crazy? If the D23 part is true, then Disney has a real nut working in the parks who is gleeful that a handful of fans are disappointed that the rumors (which seem unrealistic and bizarre) aren't true.
The CM also doesn't get that the top brass don't care about rumors on a fan board. They aren't losing any sleep between playing golf, board meetings, and vacations in Europe!
Since the rumors were, apparently, based on fan rumors, then perhaps the leaker enjoyed crashing the hopes of a handful of the diehards . . . all in the space of weeks leading up to D23.