A last point: German car exports to the US are just 20bn. So the maximum monetary damage would be 25% on this, i.e. 5bn. The real effect will be much smaller, of course, as OEMs will develop and use the best strategy. 

So the question is if it is smart to f*** up with all your old friends to win a penny. The answer is: of course, this is extremely stupid. Only if somebody doesn’t have the capabilities to understand this you might feel it is “clever”. He will learn the hard way.