I thought I would throw this out for others to consider. The request for a fishing license by a trooper without probable cause may be a violation of our fourth amendment rights. For example, just because you have a license plate on your car is not sufficient grounds for being pulled over and having your driving license inspected. The same goes is for fishing. If the officer lacks probable cause that a violation has occurred, why does a person have to present a fishing license for inspection and/or have their belongings searched? The current process is "guilty until proven innocent." Is simply catching a fish in a designated area or even fishing for a fish or dipnetting for a fish probable cause of wrong doing? Therefore, arbitrarily requesting a fishing license without probable cause of any wrong doing seems to be trending on your constitutional rights.
I found an interesting court case where John Mark Colosimo of Minnesota refused to allow a conservation officer to search his boat because the officer lacked "probable cause."
State of Minnesota, Respondent, vs. John Mark Colosimo at: http://caselaw.lp.findlaw.com/scripts/getcase.pl?court=mn&vol=apppub%5C0207%5Cc7012181&i nvol=1