People usually know its rented, so they think: lucky guy, what an upgrade, vs buying where you specifically chose for german.
That said, when I get a decent German car as a rental, trust me, the car is worth less after using it...

What annoyed me, is the fact that one wants to cancel the whole point of not driving a german car, as if there is no valid reason to it.
Obviously I don't look down on people that drive a german car, however, those people also very well understand why someone wouldn't buy a german car.