We have discussed this a few times. To answer your question about what would keep a person from simply using it as an excuse to carry without a permit would be answered by this part of the code;
only if, considering all of the attendant circumstances, including but not limited to whether the person has a valid hunting or fishing license, it is reasonable to conclude
It is what a reasonable person would believe. If a guy is walking down the street and the officer has RAS or PC to stop him and he has a pistol then it would be reasonable to conclude that he does not fall under this exemption. A person walking or driving with a backpack, again assuming there is RAS or PC for the stop, is found to have a pistol and only personal belongings in the backpack would probably not fall under the exemption. If the same person as above had survival gear and packed food in his backpack then it may be reasonable to conclude that he is in fact on his way to go hiking.