This is actually quite neat, since we find out how someone else would associate the two words where we wouldn't. However, I thing there needs to be a maximum of one or maybe two degrees of separation.
I think a few of us have decided to play obscure association:-), where we try and think of a word that is related, but not obvious
also I agree with your car/plasma example, on the other hand there is the plasmacar or plasma is a gas and a car uses gasthe Mongolian death worm is a worm that is venomous
chips