What companies will pay for advertisements on my car?

In Forza, car companies are paid to license their products; I'm guessing Electronic Arts didn't pay FN (a weapons manufacturer) to have its FN-SCAR rifle in Battlefield 4. Why do only some products in games earn their manufacturers royalty fees?

• It seems counterintuitive this is the case, as Battlefield 4 does at least as good a job simulating the product as Forza or Gran Turismo does. In fact, I own an FN FAL rifle and was first exposed to the rifle in the game Rainbow Six (before later encountering the rifle again in Congo and gaining real-world experience with FN products). It seems gun manufacturers certainly benefit from advertising their products to game-playing consumers, just like car companies do. Why do car companies get fees while gun manufacturers don't? (or am I wrong and gun manufacturers also get money in exchange for featuring their products in games?)

• Answer:

  EA used to pay gun manufacturers to use their weapons' names and likenesses in their games, but decided last year that it "wasn't worth" paying for [1]. Their belief, apparently, is that if they use the manufacturer's names they are protected by fair use [2]: "We're telling a story and we have a point of view.  A book doesn't pay for saying the word Colt, for example," EA's Frank  Gibeau told http://www.reuters.com/article/2013/05/07/videogames-guns-idUSL2N0CS2A220130507. Whether that holds up in court depends on a lot of factors, though. [1] http://www.gameskinny.com/0i83n/ea-decides-gun-licensing-not-worth-paying-for [2] http://www.eurogamer.net/articles/2013-05-08-ea-refuses-to-licence-guns-and-war-paraphernalia-its-action-games-this-yearThis answer is not a substitute for professional legal advice....