Which means that they now have probable cause to search your vehicle."
Actually, no -- that's doesn't even rise to the level of reasonable suspicion. Reasonable suspicion is only realized when the officer takes the facts known, and the inferences from those facts, that would cause an ordinarily prudent person to believe that a crime has been committed or is taking place. It cannot be a hunch.
Nervousness, in spite of the tale of Sheriff John Bunnell in an earlier post, is not enough to satisfy reasonable suspicion. There must be, as the Supreme Court has ruled, historical facts to satisfy reasonable doubt or probable cause.
According to the law, drug-sniffing dogs cannot be called to the scene unless reasonable suspicion exists -- again, this cannot be a hunch, but it must be based on facts.
Simply being pulled over for a traffic infraction does not give the officer the right to search your vehicle unless he feels his safety is threatened -- then he can only do a limited weapons search.
The point of my post? If you have been stopped for a traffic infraction, and refuse to a search for weapons, that alone cannot cause the officer to go against your wishes or call the drug dogs out.
I know that someone will reply with, "but I know so-and-so who was stopped..." I'm sorry for that person, but the law is the law. I'm speaking about the legality, not what happens. Police officers who exceed their authority should be held accountable -- that's why we must know our rights.