And companies can force a film maker to keep their official products out of a movie. Usually movie people alter products they can't be bothered with getting permission for so they don't look like a real one. That classic bug in the movie was probably altered a little, probably knocking of the VW symbol or somthing.
Besides VW is a German based company. And the case I'm talking about was tried in Germany.
Companies can force that their logos not be used. Those are trademarked and "Reserved." But, even then, it's tricky. They have to prove LOTS of stuff. And, it's decided on a case by case basis. What's usually the case is that the studio, or filmmakers, producers, whatever have a
contract with a competing brand that explicitely states they not "advertise" competing products (thus, you'll NEVER see Pepsi on American Idol).
More often than not, the studios just don't want to piss off a company because it will sour future relations for other things. THAT'S IT. But, there is no "LAW" civil or otherwise. VW cannot "forbid" anything. They just can't.
For more info see: Catterpillar v. Disney, and Mattel v. MCA Records.
And there many older cases going back to the beginnings of Hollywood (see the Ginger Rogers case).
P.S.
And usually, companies like VW have bases in the United States and bring their cases before courts here in the U.S. when it involves another American company... Trade Relations laws and treaties often dictate it (note: I do not know if this is the case with US/Germany treaties, but it's pretty standard).