It says while in the field. Your truck is not in the field. My buddy and I are going deer hunting Monday in a bear infested area and are bringing a rifle. If we are checked I don't know how they can give a ticket 
Exactly I do this all the time. One year I went blackpowder elk and straight from that camp to modern deer. I do not think they can make a case you driving down the road. There has to be a smoking gun or some intent they can prove. When are you hunting in the feild or driving down the road?
The same thing when hunting bears and you have a dog in the car. Dog cannot be in the feild.
