Even in states that won't let you carry a gun in your car , the cops have to have probable cause to start opening locked boxes in the vehicle. I've been out of the business for a long time, perhaps someone could give us an update on search and sezure law.
If the cops can find large stashes of drugs in cars and have the judge throw out the bust you would think that the law would protect you and me from illegal search.
My brother in law was in Calif. when he was stopped for traffic or something. He said he had to get his ID out of the glove box, but he had a 45 in there and he knew it was illegal, so he told the cop. The lawman said something like "your bad guy insurance huh" and never said any more about it.
Off topic, but that is a good case for looking like what you are. My brother in law has short hair, is clean cut, and generally wears working mans clothes. I kind of doubt the stop would have gone the same way if he had looked like a scumbag. As a cop when you approach someone you know nothing about you are looking for clues as to what you are dealing with, even whether the hair is glossy or dull. All of this is processed and affects the way you do your job.