I'm no lawyer, and I'm sure it's different from state to state, but my understanding in Washington state is that when you purchase and sign your license you are forfeiting your right for due cause to be searched. The fact that you possess a license enables state game wardens to search your person, vehicle and residence for game or violations with no need for probable cause or for a search warrant (not that they actively search random residences). I might be wrong but that's the way I understand it. I'm guessing it's similar in other states and that's why a warden can just drive up and "check" you or pull you over if they see you pass and check station and think you're a hunter, they can stop you and see.