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.
