We have covered this before, historically in the car industry since 1960's (my knowledge) you wore the engine in. It was accepted then that catastrophic engine failure could happpen, i.e. pistons flying through your crankcase at over 500mph was normal, and a little bit frightening!!!
As it went through the 80's due to better quality and closer tolerances on engine fittings it was not deemed neccessary.
However you have always had joints, brakes, rubberknuckles, body parts etc that its sensible to allow settling in. Also in a new car the car manufacturers give information on what to do with your car and how to run it in, for the first few weeks, you would be unwise to ignore this advice for I have no doubt they would say you were reckless, if only not to pay out in the repair costs if any thing went wrong.
I think common sense is prevalent here and just be sensible after all on the highways your not allowed to drive over 70mph are you???