I'm was never a game warden, but was able to issue citations, using the fish and game codes. We had some private reservoirs in the city I patrolled in, and because of drownings (liabilities), we were called in to issue citations for the illegal fishermen. Most of the people we caught were very cool, and we were cool with them. We would just issue a warning, and shoo them away. However, if you ran, and we had to catch you, we would throw the book at you. No fishing license, trespassing, delaying an officer, mandatory arrests were in order.
Bottom line was have your license, be cool, and your outcome will be good.