Night before the 2012 Olympic Road Race and Cav tweets "I am nervous". This is usually a good sign with Cavendish and he certainly has the best backing he could hope for in the 5 man team, radio free, 250km event. Stannard, Wiggins, Froome and Captain, Millar will be hard pushed to control the race though, and will be deprived of their usual communication to keep tabs on what is going on in the race, so it will be up to Millar to keep a close eye on events and make quick decisions during the race.
If a break gets away in the last 100km with some classics strong men, it will be hard to pull back, but the British team may be gambling that 50km from the top of the last climb is enough distance to chase down the break and get Cav to the finish in contention. Everyone else of course, will be conspiring to ensure this doesn't happen, but not likely in concert with each other, unlike the British team who will be absolutely unified in their objective as they were last year at the World Championships.
So here's my qualified (hedged) prediction, which is that the various teams with strong classics contenders will do their best to make the racing hard and wear down the British team. They will want to get rid of the weaker riders who don't race in the World Tour peloton fairly early in order to reduce the chances of crashes or being caught in the wrong side of a split. I expect a proper attack to come on the penultimate time up Box Hill, followed by the top riders such as Gilbert, Boonen (if he is over his injury enough), Cancellara, Nibali and Peter Sagan among others.
It will then be a case of whether Cavendish gets over the multiple climbs close enough to the head of the race so that the British team, or whoever is left from their earlier efforts, can chase down the break just in time to bring it all back together for a sprint finish. The riders make the race, and because of the aforementioned factors, this could prove to be one of the most unpredictable single day races for years.
If the British team pull this off, despite their race plan being perhaps the worst kept secret in modern cycling history, they will all deserve a gold medal apiece.