Well, let's simplify:
"I want to search your car"
"No"
Never, ever consent but don't resist. A search afterwards does depend upon circumstances, but the fact that you have been hunting is not probable cause to search a vehicle. A timely "free air" search by a dog without entering a vehicle or contraband in plain view are other matters. Why would a person who has nothing to hide fail to consent? Aside from general principles under the 4th Amendment, once you consent, you don't get to specify or limit the extent of the search. For example, the Georgia State Patrol would profile types of cars on the interstates coming out of Florida and pull them over. After gaining consent, some would remove door panels, remove back seats, empty the contents of suitcases and more looking for drugs. Sometimes they found drugs, sometimes they didn't, but once there was consent, there was no complaining about the extent.
Consent can be withdrawn at any time. The person giving consent must be present during the search so he can withdraw consent. However, by that time, the LEOs almost always have seen enough PC to get a warrant. Which a smart one will do.
Also, the profiling search for drug dealers was declared unconstitutional several years back. It was developed by DEA agents in Atlanta. Cars with rental FL plates, with two people in the car of S. American appearance, and driving strictly by or below the speed limit were profiled. They confiscated a lot of money and cocaine until profiling in general was declared unconstitutional.
The reason consent was not withdrawn is because most of the drivers were from Columbia and probably didn't know they had the right to refuse...if they had a right to refuse. For a long time, the profile was solid PC,and no consent was needed.
Hunting is not PC to search your car, but it is PC to check your license and your gun.
I wouldn't say "Never, ever consent." If you've got nothing to hide, why not consent? On principal? I'd ask, "For what reason?" just for a professional curiosity's sake. You'll likely save your self some time by consenting and possibly a traffic ticket for whatever the cop stopped you for in the first place.
