I agree, self preservation is the key here, and I was in no way advocating people should do anything other than hand over the keys if caught in a situation.
Though I think its far better to try and avoid the situation altogether, as in the case with the Yamaha owner, we don't know if they wouldn't have still shot him in the foot to stop him pursuing them, there's no guarantee that handing over the keys wont result in you still getting a battering or worse.
It's important to remain vigilant - has the same car been behind you for a particularly long period of time?
Allow for an escape route - always ensure you have left a big gap between you and the car in front when at junctions and traffic lights etc.
Aware of your surroundings - Are there people hanging around traffic lights or good spots for people to hide from view?
Be secure - Always keep your doors locked. A failed attempt to open the door will buy you valuable seconds to drive off.
Be Suspicious - The gentle rear end shunt is a common favourite to get you out your car, if you suffer this then be on your guard, make them get out their car and come to you, lower the window slightly with the door locked and get them to follow you to somewhere you will feel safer parking to exchange details. If they're genuine they wont object if they do then take down there registration and call the Police.