Shytorque,
Firstly I would have thought a Puma crew (of 3 or 4?) would be able to defend themselves from an irate farmer, surely they deal with tougher situations in warzones? Secondly, the average non flying member of the public has no idea what the controls in a helicopter actually do, and it's a bit extreme to assume an angry man will open the door and suddenly grab the conrols! What is there to stop any idiot walking into a rotor any time we land in a public place, whether they are angry at the helicopter pilot or not? Most normal people have the common sense not to do that, the same as most normal people have the common sense to look both ways for traffic before crossing the road...