I was the Events Coordinator for the Southwest Mopar Club in El Paso, Texas. We were a nonprofit organization and we were registered with tax id and all of the legal red tape that goes with it. We had to submit all of this to Chrysler/Dodge to be able to use the "M" logo and the word Mopar.
I also have a friend in Mississippi that makes waterslide decals for scale model trucks. He has been sent a cease and desist from both Kenworth and Peterbilt. He won't go anywhere near making beer company decals.