If tey say it and they "happen" to "find" Bin Laden during the election they can turn it into a big conspiracy... if he doesn't turn up between now and 02 Nov then nothing will happen. Nobody will go after the people spreading this rumors and punish them for it. It's just disappear.
Odds are, even if they did have him in custody, this rumor has been floating around long enough that it would be stupid to go through with the "look who we found just in time for election" plan. If they had any sense, they;d simply kill his ass and show the world his head separated from his body. If he had an control over terrorist cells we'd have picked it up through the various forms of traffic that our intel community monitors. But he obviously doesn't and therfore serves no purpose to us alive.
They should have done the same thing to Saddam, but the media pretty well ruined any chances of that...