Legal Question in Native American Law in California

If you violated tribal law and the victim does not press charges (i.e. accuse you of a crime) then the tribal government can still charge you as you still may have violated the law. Practically speaking if the victim does not cooperate with the prosecution then its unlikely. By the way the Casino is not the tribal government.

Grand theft at an Indian casino, even if the casino is "Indian territory," would come under the Major Crimes Act, as amended, and jurisdiction would be in U.S. Federal Court or state court, and not tribal court. Probably Federal, assuming the casino is Indian territory. Then, what do you mean by "press charges?" People are required to appear in court for a criminal trial by prosecuting attorneys by indictment or information, which they may do following a police report or upon being informed about a crime by a citizen. So, in a sense, anyone who knows about a crime that's been committed can "press charges," in another sense, the defendant is only haled into court after a prosecutor (D.A.) prepares, files and serves the required document (indictment or criminal information).