If a game has models, textures, music from other games (i.e. copyrighted material), it is obviously illegal to distribute that game. If the author of the illegal game (say person A) sends the game to someone to play (say person B), for free if it makes any difference, and person B contacts the original authors, will person A get sued or just asked to stop? Can they prove that those resources were sent by person A at all?
Also, is there something that person A could do to mitigate the repercussions? Like putting in a disclaimer like "I do not claim to own any of the material in this game" (I've seen that in Youtube videos sometimes).