And it is a huge gamble on which one you would get. Too large of a gamble.
My sister is an attorney and her advice was this — lock your car door, close it and ask the local cop to call in a state police officer to witness the search if they insist on a search.
A friend of mine in high school was kissing his girlfriend when the friendly tap on the window from a local cop occurred. Instead of telling them to move along, the cop insisted on a search of his vehicle. He closed & locked the car and asked for a state police officer to be present during the search. The cop was annoyed because his integrity was questioned, but he let him go with a "don't come back here" warning.
It's like deterring a burglar - they'll just move on to an easier target. The phrase "I don't consent to any searches today, officer," should be a standard part of everyone's vocabulary.